# My PM-1640TL lathe, also known as TL-1640



## xyz (Aug 30, 2021)

This thread is about my PM-1640TL also known as TL-1640 which I received in August, 2021.  I had placed the order at PrecisionMatthews.com only weeks earlier.  It was ordered with DRO and the taper unit installed.

I was posting to the thread "PM-1660TL" which was started by @erikmannie in June, 2020.  He was kind enough to ignore that I was posting about a TL-1640 on a PM-1660TL thread.  Another member kindly suggested that I start a tread.  Now that I look at the title of @erikmannie 's thread, it is indeed titled "PM-1660TL".  So, this thread is the result of following that suggestion.

Try searching for how to start a thread on a site devoted to machining:  lot of interesting threads that will be helpful when my lathe is finally operational.  In the end, it is quite easy to start a thread here, unlike on some other sites.

So, the machine arrived on a flat bed truck with a fork lift and I took delivery in front of the garage, on the parking pad.  After uncrating, initial cleaning, and moving it to its location in the garage.  Only a little more cleaning was required.  Most of the cleaning was done outside.  It had been planned that way because I didn't know what toxic fluids would be finally required.  There are many suggestions on the internet.  As it turns out, the machine was coated with an easily removable sealant.  Nothing nastier than WD-40 was required in most places.  

The machine survived it's journey with no visible mishaps.  There were only very minor dings, hardly noticeable, really, but of course, I had to touch up the dings before it was moved to its planned location.

I tried every control that I could as an initial check.

The markings on the apron on how to engage the power feed for carriage drive or cross feed drive is counter intuitive, to me anyway.  It's bass-ackwards.  I'll confirm this after the machine is powered up.

The threading dial indicator, when it is disengaged from the lead screw, interferes with the power and direction handle when the handle is raised.

The cross slide hand wheel was very stiff, requiring both hands to turn it.  I followed many suggestions from members here, and the hand wheel became much freer.  But I did have to get assistance from Precision Matthews.  I was prepared to hold for hours or play phone tag, as when I have to interact with one of my banks.  But within minutes I was talking to a real person.  He said he knew my problem from my postings here on Hobby-Machinist.   He suggested that I look at the mounting of the taper unit to the back of the carriage.  It may have shifted during transit.  It was good advice and now I have a cross slide hand wheel that can be turned by one hand, and more importantly, I feel comfortable that I can apply power to the cross slide.

My garage floor slopes a bit and it required a half inch shim at the tail stock end for it to be leveled.  All six feet are sitting on a single concrete slab.  The goal of leveling is to take out the twist in the bed.  The trick to leveling is to use a high grade machinist level that has a calibration or fine adjustment for itself  and follow the level manufacturer's instructions on how to use the level.  Then plan on iterating the leveling many times.  After all, there are six feet and they all interact to twist the bed.  During my final iteration, a very small turn of the adjusting bolt of about 10 degrees made a noticeable difference in the bubble.  Ten degrees is about a minute and a half on the face of a mechanical watch.  The rounded end of the adjusting bolt sits in a dimple of a cast iron (I am guessing) disk.  The disk itself has four protruding portions that interfaces with the concrete.  I am betting that after the machine vibrates, in days or in weeks, there will be settling and the machine twist will have to be adjusted again.

Now the machine looks almost like PM's advertisement photo, including even the impossible to read directions of the threading dial from a standing position. 








I am at a point now of integrating the Hitachi WJ200-075LF which was also purchased form Precision Matthews with the PM-1640TL.  I posted my understanding of the electrical aspects of the lathe, using the supplied electrical diagrams.  My main concern is to preserve the safety circuits of the original lathe.  My goal is to make as few modifications as possible and if wires are removed from the circuit, to leave them in place or near the original locations so that all can be undone by some other person at a later time.

I posted several observations about the safety circuits at the thread "PM-1660TL" and was about to post some conclusions there.  Thereafter, postings about my PM-1640TL TL-1640 will continue in this thread.


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## xyz (Aug 30, 2021)

As I was working through all the gears on the TL-1640, PM-1640TL,  I was reminded of when I learned to drive a stick shift.  I was taught to double clutch.  I didn't know how that worked, really, but it avoided that awful grinding noise.  I imagined that releasing the clutch in neutral told the gear box some magical instructions.  Then the clutch peddle was pushed down again before the gear handle was moved to the next gear.

The lathe manufacturer must have had a lot of torn up gears from users shifting under power for them to have a warning plaque on the front panel.

I found the gear box to be really tight, which is a good thing, I think.   It is much easier to put the head stock in neutral, change speeds, and then put the gear box in low, med, or high.  All this is done manually not under power, not using the jog.

It will be important to know that the gears are in full mesh before a 5 horse power motor is applied.

So, how do you know that the gears are in mesh, other than it feels good.


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## BladesIIB (Aug 30, 2021)

I think you will find it is pretty easy to tell when the gears are engaged. They are either fully engaged or fully disengaged, they don’t hang out half way in my experience. The slight movement with your hand on the Chuck is for alignment and then then they will mesh nicely. They don’t have synchros like a manual transmission in a car. When engaging the gear box, you will know when fully engaged when the feed rod or lead screw turn when turning the headstock. If you ever turn the lathe on when something is not engaged you should not get grinding, you just won’t get the desired action. Let the motor stop completely and engage the gears and power on again. 

I think you will find the feed on the apron quite intuitive when you start machining and nothing backwards about it. The apron has a quick change gearbox unlike many other lathes. This allows you to change feed direction while under power, quite a nice feature.

When you disengage the thread chasing dial it only needs to come down far enough to disengage the gear and when you tighten it there it will not interfere with powering the lathe. As for reading it standing up. The only part you. We’d to read standing is there dial which you can quite clearly. The table on the side you check when setting up your thread and it is in a good place to save you having to pull out the manual. 

I hope that helps, I think you will find it is a really nice lathe to operate when you get it powered up.


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## matthewsx (Aug 30, 2021)

Congratulations on getting your new machine up and going. Your methodical approach should serve well as you become more familiar with the machine and processes.

My only comment is about installing the VFD. There’s really no good reason to leave abandoned wires in place for an imagined future owner who wants to restore it to factory condition. Just document your work and label things appropriately. The factory wiring diagram can be kept along with your documentation and that should be sufficient for you or anyone else in the future, extra wires would probably just create confusion.

@mksj is the go to source for all things VFD on here as you’ve probably figured out.

And…..

Pictures


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## Janderso (Aug 30, 2021)

Your bottom panel-gear box, is laid out exactly like my 1970's Clausing Colchester 15X50. When I first got the lathe I couldn't get the thread feed to work. Same thing, one of the paddles was just not clicked in all the way. Once you get the hang of it, piece of cake.


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## xyz (Aug 30, 2021)

BladesIIB said:


> I think you will find it is pretty easy to tell when the gears are engaged. They are either fully engaged or fully disengaged, they don’t hang out half way in my experience. The slight movement with your hand on the Chuck is for alignment and then then they will mesh nicely. They don’t have synchros like a manual transmission in a car. When engaging the gear box, you will know when fully engaged when the feed rod or lead screw turn when turning the headstock. If you ever turn the lathe on when something is not engaged you should not get grinding, you just won’t get the desired action. Let the motor stop completely and engage the gears and power on again.
> 
> I think you will find the feed on the apron quite intuitive when you start machining and nothing backwards about it. The apron has a quick change gearbox unlike many other lathes. This allows you to change feed direction while under power, quite a nice feature.
> 
> ...


Thanks for the encouragement.  Overall, it has been a positive experience.  Power next.


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## mksj (Aug 30, 2021)

I have the same gearbox, everything is a bit stiff to start out. When changing the headstock speeds there is usually a detente feel when the gear level clicks into place. The key is to turn or rock the spindle/chuck manually when changing gears so they smoothly engage. When changing the feed/thread gearbox gears the same applies and you must also have the gear train engaged so typically the gear level is in L.  It also takes a bit more spindle movement and it there is a distinct feel when the gears engage. I always use the VFD jog (6Hz) to verify that everything is engaged after I change any of the gears. Once you get the hang of it all it very straight forward as others have mentioned. The momentary Jog, just verifies everything without spinning everything up to speed. The universal gearbox is a real dream to use if you do a lot of different threading and switch between metric/imperial threading which I do quite a bit.


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## xyz (Aug 30, 2021)

Janderso said:


> Your bottom panel-gear box, is laid out exactly like my 1970's Clausing Colchester 15X50. When I first got the lathe I couldn't get the thread feed to work. Same thing, one of the paddles was just not clicked in all the way. Once you get the hang of it, piece of cake.


Thanks.  I guess I only used old beat up lathes, where the gearing was sloppy.  A new machine is a rewarding experience:  no one else has had a chance to mess it up.  It will be only me!


mksj said:


> I have the same gearbox, everything is a bit stiff to start out. When changing the headstock speeds there is usually a detente feel when the gear level clicks into place. The key is to turn or rock the spindle/chuck manually when changing gears so they smoothly engage. When changing the feed/thread gearbox gears the same applies and you must also have the gear train engaged so typically the gear level is in L.  It also takes a bit more spindle movement and it there is a distinct feel when the gears engage. I always use the VFD jog (6Hz) to verify that everything is engaged after I change any of the gears. Once you get the hang of it all it very straight forward as others have mentioned. The momentary Jog, just verifies everything without spinning everything up to speed. The universal gearbox is a real dream to use if you do a lot of different threading and switch between metric/imperial threading which I do quite a bit.


Thank you for  VFD 6Hz, etc.

I have a circuit modification drawn out, but I am rereading the Hitachi documents to see what I missed, if any: 
"Sizing Three-Phase Inverters for Use with a Single-Phase Supply",​"WJ200 Quick Start​"WJ200 Series Inverter Quick Reference Guide​"WJ200 Series Inverter Instruction Manual​and of course various documents that you and others have posted on the internet.​
TL-1640 is a dream come true.  And I haven't powered it up yet.  It's literally a dream come true.  I've been looking at PM machines for about 10 years.  And, when playing cards my mind would wander thinking about one lathe or another.  Last month I decided to wait no longer.  Too many uncertainties.

Another shop essential has been planned for:  a shop cat.  I hate field mice, but we also have pack rats that destroy engine wiring.  I don't need no mice feeding on the lathe wiring.


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## xyz (Aug 31, 2021)

When reviewing Hitachi "WJ200 Series Inverter Quick Reference Guide", on page 91, (it's also in "WJ200 Series Inverter Instruction Manual".  I see a diagram of how to provide for a an interrupting device utilizing EDM output to reconfirm both safety inputs GS1 and GS2.

They use G9SX-GS226-T15-RC.  It's listed for $600+, and on ebay its advertised for $400.  Yikes.








If the goal is to signal via GS1 and GS2 when the emergency button is pressed, there is a way to do so with out the use of G9SX-GS226-T15-RC, that is, by using the emergency button on the lathe and routing the signals through unused relay contacts.

That will be included on the modified diagram to be posted soon.


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## xyz (Aug 31, 2021)

My Hitachi downloaded manual is missing Section 5, but I found this page online having to do with braking resistor values. 

See the entry for WJ200-075LF, below: The minimum resistance is 17 ohms, which results in a four fold increase in braking torque.  Good thing there are two 35 ohm resistors on order.  They were the lowest valued resistors available from within USA.


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## BladesIIB (Aug 31, 2021)

In the wiring diagram below for my PM 1440TL I have all the native safety features of the lathe still in full operation.  The safety stop is still fully functional. The emergency brake pedal is still an emergency stop (with an added switch for a free run command) and in addition to the lathe safety, I have a VFD unattended start in case the forward or reverse lever on the lathe is left on when the VFD is turned on. All this is possible without the $400 inverter you have shown above.  I am not a certified electrician, but here is the wiring diagram for my VFD wiring on my 1440TL with the Hitachi WJ200.


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## xyz (Aug 31, 2021)

BladesIIB said:


> In the wiring diagram below for my PM 1440TL I have all the native safety features of the lathe still in full operation.  The safety stop is still fully functional. The emergency brake pedal is still an emergency stop (with an added switch for a free run command) and in addition to the lathe safety, I have a VFD unattended start in case the forward or reverse lever on the lathe is left on when the VFD is turned on. All this is possible without the $400 inverter you have shown above.  I am not a certified electrician, but here is the wiring diagram for my VFD wiring on my 1440TL with the Hitachi WJ200.


Thanks for the drawing.

Nor, am I an electrician.  More the reason why I want to understand the original circuit diagram and the functions.  I also want to understand why professional power engineers use use G9SX-GS226-T15-RC.

If the functionality can be provided without its use (or, if it is not necessary in a home power installation), then all the merrier.  Who wants to spend an extra $400 ?

It's always helpful to see how others have solved the problem, so I appreciate your response.

I'll post when I fully understand the G9SX-GS226-T15-RC.

Thanks again.


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## BladesIIB (Aug 31, 2021)

Read up on source logic vs sink logic as you read up on programming your WJ200. For external controls as shown I my diagram my WJ200 is set up for source logic. That allows the control wires to tell the VFD what you want it to do. Great to understand the full details of your lathe and how the interlock works etc. but keep in mind you won’t be changing any of that functionality with your VFD install in a basic install. And if you do a full install then you would be pulling all native wiring out.  If you read through what Mark has posted on the VFD Install using the lathe contactors you will have all you need.  If you have a specific question, ask and we will try to get you a specific answer.


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## xr650rRider (Aug 31, 2021)

If you required safety instrument system (SIL1, SIL2, SIL3) you might use the relay they suggest.  Probably is UL listed, has documented MTBF numbers all requirements for insurance purposes.  Way off in the weeds for your lathe.  Still won't keep you from twisting your arm off, if you wear a long sleeve shirt.  Your lathe, if it's anything like any of the other PM machines, will have a latching relay.  If your using the lathe and power fails, when power is restored, the lathe won't restart until you move the handle from forward/reverse back to off and then back to forward/reverse.  Same thing by pressing the E-stop, or the foot brake.  The latching relay provides that functionality and is your safety interlock and definitely worth keeping.  I would think your time would be much better spent studying Marks schematics on the PM-1440 as it has the foot brake.  Since your machine is new, keeping existing contactors and removing the high voltage side (as he's mentioned a couple times to you), allows passing the P24 control voltage signal thru the motor contactor and into the drive as a forward or reverse input.


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## xyz (Aug 31, 2021)

BladesIIB said:


> Read up on source logic vs sink logic as you read up on programming your WJ200. For external controls as shown I my diagram my WJ200 is set up for source logic. That allows the control wires to tell the VFD what you want it to do. Great to understand the full details of your lathe and how the interlock works etc. but keep in mind you won’t be changing any of that functionality with your VFD install in a basic install. And if you do a full install then you would be pulling all native wiring out.  If you read through what Mark has posted on the VFD Install using the lathe contactors you will have all you need.  If you have a specific question, ask and we will try to get you a specific answer.


Thanks again.

I try to limit newbie questions until I have tried reading and understanding the documents and other people's works.

But, there will be plenty questions coming, I'm sure.


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## xyz (Aug 31, 2021)

xr650rRider said:


> If you required safety instrument system (SIL1, SIL2, SIL3) you might use the relay they suggest.  Probably is UL listed, has documented MTBF numbers all requirements for insurance purposes.  Way off in the weeds for your lathe.  Still won't keep you from twisting your arm off, if you wear a long sleeve shirt.  Your lathe, if it's anything like any of the other PM machines, will have a latching relay.  If your using the lathe and power fails, when power is restored, the lathe won't restart until you move the handle from forward/reverse back to off and then back to forward/reverse.  Same thing by pressing the E-stop, or the foot brake.  The latching relay provides that functionality and is your safety interlock and definitely worth keeping.  I would think your time would be much better spent studying Marks schematics on the PM-1440 as it has the foot brake.  Since your machine is new, keeping existing contactors and removing the high voltage side (as he's mentioned a couple times to you), allows passing the P24 control voltage signal thru the motor contactor and into the drive as a forward or reverse input.


Thanks for the suggestions.  Been doing that, studying what others have done and relating that to what came with the machine, and what industrial engineers require for safety.  I just want to know.

What I implement will most likely have been done by others, already.


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## xyz (Sep 1, 2021)

Performance level d, PLd, about one in a million no action when the emergency switch is pressed:

To achieve better than one in a million failure of the emergency shut off function, known as performance level d, PLd, the ISO standard requires two separate circuits from the emergency switch to the WJ200 VFD:  those two circuits are GS1 and GS2.  Furthermore, the circuits must be tested at least once a year.  If there is inconsistency in the GS1 and GS2 signals, then EDM is activated by the VFD and manual intervention is required.

The performance level is no better than that of any intervening circuit, relay contacts, or electronics and any intervening item degrades the performance level.

The activation of the reset switch informs the VDF that a person has seen that there is a problem with the redundant emergency circuit. The person ought to look for crushed or cut wires, or fused contact points (if relays are used), or failed intermediate electronics.

The emergency switch found in my TL-1640  PM-1640TL is PPFN1R4N with one PL004001, and it can take additional contact modules, both NO or NC.  Adding contact modules to this switch body is the way I will be going.   I don't want any additional components whatsoever between the emergency switch and the Hitachi VFD.  If I don't mind using a vacant switch contact in K4, then adding contact modules to the emergency switch not necessary, but that would introduce a potential failure point and would jeopardize the PLd of better than 1 in a million fault or non activation after the emergency switch is pressed.

The addition of two contacts to the switch will enable me to implement GS1 and GS2 functionality as described in the "WJ200 Series Inverter Instruction Manual", Section 4, page5.  This functionality is also described in "WJ200 Series Inverter Quick Reference Guide", page 89. 90, and 91.  The G9SX-GS226-T15-RC is a box that interfaces the emergency switch and provides for resetting the WJ200. 

I don't see why it is required.  It can only degrade the performance level.  Perhaps in a multi WJ200 installation it serves an additional purpose.







A portion of the diagram from "WJ200 Series Inverter Instruction Manual", Section 4, page 5, helps put the signals in context. The GS1 and GS2 are on pins 3 and 4 on the left side.  EDM is on pin 11 and its common is CM2 on the right side o that diagram.











[SK]


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## xyz (Sep 6, 2021)

Its been a week since I leveled the lathe.  I checked today and the bubble has moved about three ticks.  Also, oil has collected toward the front in the U shaped groove at the bottom of the carriage, indicating the level is telling the same story.  The weather has become noticeably cooler in the past week.  Maybe that has caused the change.  I think it has to do with initial settling in of the leveling pads.  I'll give it a few more days before re leveling it.

I can check for head nod and alignment after I have power to the lathe.

I like Joe Pieczynski's explanation about those issues.  His highly informative model of the 6-point contact and the distortions caused by them is very instructive.  His video is at


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## xyz (Sep 8, 2021)

My Pm-1640Tl (TL-1640) came with an emergency switch whose part number is PPFN1R4N (the mushroom button) with one PL004001 (a NC switch).  It's a modular set up and the emergency switch can take as many as five independent normally open, NO, or normally closed, NC, switches or poles.  The mushroom switch locks when pushed; a piston pushes on each of the actuators of the installed switches;  twisting the mushroom releases it.

In order to follow what Hitachi indicates, that is direct connection from the emergency switch to the VFD, I ordered the components to add additional poles or switches to the mushroom.  The following pictures show the components and what it looks like when assembled.  There is room in the 1640 itself (behind the midsection of the front panel) to add additional poles.

Much of the parts is plastic.  I could see a failure in which not the contacts themselves, but the plastic parts fall apart.  Hitachi's circuit is doubly redundant, so two switches have to fail before there is a critical problem.  I guess that's the purpose of the redundant and direct communications from the emergency switch to the VFD.

This not the switch from the machine, but what's in the machine looks like it.






This picture shows the components that can be assembled.





And, here is a picture of the switch with five independent poles assembled as one 'emergency switch'.


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## xyz (Sep 9, 2021)

I rough cut lumber for a platform for the PM-1640TL and did a check to see if the parts come together.  My jointer is away for warranty repair, so finishing this will have to wait until it comes back.  The goal is to make the platform water and oil tight in anticipation of splashes and drips.

Also, now my eyes are at the level of a six-foot guy.  I can see what they would see. 

There are two 1x4 boards running left to right, under the long edges.  They touch the painted garage floor and will remain unsealed.  Next level is composed of 2x4's running perpendicular to the ways.  They are spaced so that a pallet jack can be used to move it.  The platform is composed of a 2x4 and four 2x6's making it about 25 inches when finished.  When they are put through a jointer and a thickness planer, then glued, and sealed with spar varnish, then the platform will be water and oil tight.  If I drop a tool it will hit wood, not cement.  The platform is firm, but I bet it will be gentler to my feet and knees than concrete.

Nothing goes on the platform.  House rules.  There will be nothing to trip over.


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## xyz (Sep 10, 2021)

Does anyone have written documentation for the motor in the PM-1640TL ?  I just talked to PM.  I am looking for the insulation class which will tell me the allowable temperature rise.

Class A would mean 60 C deg allowable rise from ambient of say 25 C deg, which would mean 85 C, (185 F deg).  Omega has a thermistor that is 3K Ohm at about this temperature: part number 44008 44032.

Class B means 80 C deg rise above ambient; class F is 105 C deg above; and class H is 158 C deg above.  


I don't see the standard NEMA class for the winding insulation on the name plate on my motor, so I don't know what class it is.  I'll take a photo of the name plate, if I can get my camera to focus on the name plate.

I can go with the least favorable class A, which would cause an earlier shut off than if it were of a better winding.

So far, this is what I know about the motor in my machine:  

YOUBA Induction Motor: Searching YOUBA on the internet leads to a motor company in China, but that company does not list this motor.
3.7 KW 5 HP 
Serial NO: YB...76
Type AE EF (I cannot find what AE EF means).  On a NEMA name plate, Type is reserved for company specific information.
Poles 4; 
IP 54; 
60 Hz 220/440 Volts
Amps 14/7.0
RPM 1720

Inside of the wiring box, it is wired for Low Voltage: U2, V2, W2 are bussed together; R is connected to U5 and U1; S to V1 and V5; T to W1 and W5.  This motor can be wired for 440 Volts.



Here is what the Hitachi WJ200 manual says about thermal shut off:

It requires a thermistor at 3,000 Ohm when the temperature reaches the motor shut off temperature.

Page A-7















Page 3-85






Page 4-5








Page 4-6:  Look for PTC(5) below














Page 4-30







Page 6-6


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## mksj (Sep 10, 2021)

Insulation on the motor is "E". There are no thermistors on these motors, you mostly see them with vector type motors.  The rated maximum Hz of these motors is around 72Hz although I run mine to 80Hz.

I will only make this comment once, given that multiple others have also mentioned the same thing. It is one thing that you want to understand how things work, but you are overthinking almost all aspects of the control system and the purpose/application of many of references within the VFD manual which apply to industrial application and are more for legal shielding/warnings, vs. application in the use/environment the machines will be used as a hobbyist/single user.  You need to determine the purpose of the E-Stop as to how it applies to what you want it to do vs. safety systems in industrial settings where the purpose may be entirely different. In the simplest form you want an E-Stop to kill power to the control contactors/relays if they are used for signal transmission, and for redundancy independently block the VFD singling for motion with a separate E-Stop switch. It may also be desirable to do a fast or emergency stop braking if the VFD is capable of doing so without tripping an over voltage buss run. The basic VFD install that BIIB did is one approach that outlines these aspects. Alternative is a complete different native control system with 2-3 levels of redundancy, that has components that have a high reliability, and any fault results in a system shut down.


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## xyz (Sep 10, 2021)

mksj said:


> Insulation on the motor is "E". There are no thermistors on these motors, you mostly see them with vector type motors.  The rated maximum Hz of these motors is around 72Hz although I run mine to 80Hz.
> 
> I will only make this comment once, given that multiple others have also mentioned the same thing. It is one thing that you want to understand how things work, but you are overthinking almost all aspects of the control system and the purpose/application of many of references within the VFD manual which apply to industrial application and are more for legal shielding/warnings, vs. application in the use/environment the machines will be used as a hobbyist/single user.  You need to determine the purpose of the E-Stop as to how it applies to what you want it to do vs. safety systems in industrial settings where the purpose may be entirely different. In the simplest form you want an E-Stop to kill power to the control contactors/relays if they are used for signal transmission, and for redundancy independently block the VFD singling for motion with a separate E-Stop switch. It may also be desirable to do a fast or emergency stop braking if the VFD is capable of doing so without tripping an over voltage buss run. The basic VFD install that BIIB did is one approach that outlines these aspects. Alternative is a complete different native control system with 2-3 levels of redundancy, that has components that have a high reliability, and any fault results in a system shut down.
> 
> View attachment 377964


Thanks for the photo.  I looked again, and I also took a photo.  I had missed the "INS E"


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## xyz (Sep 10, 2021)

I looked again at the motor face plate and I had missed the "INS E" which means that the motor can run 15 C deg hotter than class A, which could run as high as high as 100 C deg.  At this altitude, that's above boiling point of water



Class E​*Class E* insulation consists of materials or combinations of materials, which by experience or tests can be shown to be capable of operation at Class E temperature (materials possessing a degree of thermal stability allowing them to be operated at a temperature 15 Centigrade degrees higher than Class A materials).
_*Maximum allowed temperature: (IEC60034-1 only): 120C, 248F.*_


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## xyz (Sep 10, 2021)

I talked to Hitachi technical support and was told to look into "KlixOn" brand thermal switch.  I see that there is such a brand, but I haven't found any spec sheets, yet.

Also, if I were to wander away from Hitachi manual's directives, it seems modern semiconductor integrated circuits could also solve the problem:  but then, who or how would the IC and the supporting circuit be confirmed to fulfill the functional requirements?

Since I now know that my motor is "INS" class E, I know at what temperature the thermistor has to be 3,000 ohms.  It's what Hitachi manual suggests.  My intent is to try to follow the book.

Omega.com part number 44008 44032 is 3,073 ohms at 85 C deg.  That's 60 C deg above ambient 25 C deg, and well within "INS" class E.

There must be other thermistor manufacturers.

Studies have shown that the temperature near the output shaft (near the bearing) is only a few degrees different than the temperature of the windings.  Attaching the thermistor there is what I plan to try.


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