Vfd for an old 3hp lathe

[mksj]

Suit yourself on the VFD, there are also a lot of things that you may not know about the HY VFD's. For everyone that works there is one that doesn't or people run into programming/function issues. A 3Hp VFD should be on a 30A breaker, so 10AWG input 230VAC. Motor cable is 14G, 3 conductors and a ground. Technically it should be 600V rated or higher due ti the PWM voltage delivered, the motor rated voltage is RMS not peak voltage. You can pick up various small amounts of wire on eBay, also Automation Direct has very good pricing. I do not know anything about your lathe, so how you are going to hookup the VFD and wire it in is unclear. They are not a 3 phase power source to the lathe, the motor is wired directly to the VFD. It is not good practice to wire the spindle switches directly to the VFD low voltage control circuits, and if there is a foot brake it needs to put the VFD into a freerun mode when operated and not restart the lathe when released. HY comes in many variations, I installed one many years ago on a lathe, it had terminals for an external braking resistor but no circuitry inside to operate it. I never used another one since. RIP. Neutral wire you can split out 120VAC circuits but it needs to be on a separate 15A breaker.

https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/general_purpose_vfds/gs21-23p0

 

[MikeInOr]

I was planning on running a circuit just for the lathe. Maybe overkill but 12-2 is considerably cheaper than 12-3.

12/3 will allow you to run the VFD on 220v AND have a 110v supply for a light or 110v coolant pump, etc.

If it were me I would run 12/2 and if you have any 110v accessories plug them into a 110v outlet. (Actually this is exactly what I do!)

P.S. My DRO will run on 110v or 220v and auto switch based on the incoming voltage.

I can get a

Huanyang Vfd,Single to 3 Phase,Variable Frequency Drive,3Kw 4HP 220V Input AC 13

For $110 shipped. It has enough to power the f.l.a. of the 3 hp motor at around 10 amps so there is some wiggle room.

I cannot afford an expensive vfd. I'm hoping this one will do for the limited hobby use this lathe will see.

This should work perfectly for hobby use and last many years.

Found this one. In the listing it says to upsize for heavy loads so this is for 4hp.

Huanyang Vfd,Single to 3 Phase,Variable Frequency Drive,3Kw 4HP 220V Input AC 13 | eBay

220v 3kw 4HP VFD Specifications. There is enough space for cooling between each component, and the product casing is designed with multiple holes, the above features can make this VFD have a longer service life.

www.ebay.com

I would buy that one it it were my Lathe. One cravat, I am pretty sure the 4hp HUANYANG does not support an EXTERNAL braking resistor. If you want to use an external braking resistor contact HUANYANG through Amazon and request external braking resistor support for a $20 up charge. It does support internal braking though. My 7.5hp on the 10hp HUANYANG does not have an EXTERNAL braking resistor and the blade slows down in about 3 seconds with the internal braking.

My Hitachi VFD DOES have an external braking resistor connected up to it BUT when I have tried to get it working I screw up the VFD parameters and the VFD completely stops working until I do a factory reset. My SB 13 slows down in about 3 seconds using the internal braking on the Hitachi VFD WITH THE EXTERNAL BRAKING RESISTOR DISABLED. Some day I will work up the courage to try to enable the external braking resistor on the Hitachi VFD / SB 13 lathe.

An EXTERNAL braking resistor should stop the motor turning in a shorter period of time. It would be nice to have an external braking resistor working on both my Lathe and RAS. Both currently come to a stop much quicker than when the machines were running on my RPC with no braking what so ever.

 

[Batmanacw]

12/3 will allow you to run the VFD on 220v AND have a 110v supply for a light or 110v coolant pump, etc.

If it were me I would run 12/2 and if you have any 110v accessories plug them into a 110v outlet. (Actually this is exactly what I do!)

P.S. My DRO will run on 110v or 220v and auto switch based on the incoming voltage.


This should work perfectly for hobby use and last many years.



I would buy that one it it were my Lathe. One cravat, I am pretty sure the 4hp HUANYANG does not support an EXTERNAL braking resistor. If you want to use an external braking resistor contact HUANYANG through Amazon and request external braking resistor support for a $20 up charge. It does support internal braking though. My 7.5hp on the 10hp HUANYANG does not have an EXTERNAL braking resistor and the blade slows down in about 3 seconds with the internal braking.

My Hitachi VFD DOES have an external braking resistor connected up to it BUT when I have tried to get it working I screw up the VFD parameters and the VFD completely stops working until I do a factory reset. My SB 13 slows down in about 3 seconds using the internal braking on the Hitachi VFD WITH THE EXTERNAL BRAKING RESISTOR DISABLED. Some day I will work up the courage to try to enable the external braking resistor on the Hitachi VFD / SB 13 lathe.

An EXTERNAL braking resistor should stop the motor turning in a shorter period of time. It would be nice to have an external braking resistor working on both my Lathe and RAS. Both currently come to a stop much quicker than when the machines were running on my RPC with no braking what so ever.

Do you think that a lathe from the 20's or 30's will be able to run an internal braking setup? I never considered that being possible.

There is no foot brake. The lathe is way too old for that.

 

[Batmanacw]

Suit yourself on the VFD, there are also a lot of things that you may not know about the HY VFD's. For everyone that works there is one that doesn't or people run into programming/function issues. A 3Hp VFD should be on a 30A breaker, so 10AWG input 230VAC. Motor cable is 14G, 3 conductors and a ground. Technically it should be 600V rated or higher due ti the PWM voltage delivered, the motor rated voltage is RMS not peak voltage. You can pick up various small amounts of wire on eBay, also Automation Direct has very good pricing. I do not know anything about your lathe, so how you are going to hookup the VFD and wire it in is unclear. They are not a 3 phase power source to the lathe, the motor is wired directly to the VFD. It is not good practice to wire the spindle switches directly to the VFD low voltage control circuits, and if there is a foot brake it needs to put the VFD into a freerun mode when operated and not restart the lathe when released. HY comes in many variations, I installed one many years ago on a lathe, it had terminals for an external braking resistor but no circuitry inside to operate it. I never used another one since. RIP. Neutral wire you can split out 120VAC circuits but it needs to be on a separate 15A breaker.

https://www.automationdirect.com/adc/shopping/catalog/drives_-a-_soft_starters/ac_variable_frequency_drives_(vfd)/general_purpose_vfds/gs21-23p0

The maximum amp draw from the vfd is 13 amps. The motor will draw 10 fla. I'm not seeing how a 20 amp circuit isn't enough.

You seem to claim a 50% failure rate on that particular brand of vfd. Any substantiation of that claim?

 

[MikeInOr]

Do you think that a lathe from the 20's or 30's will be able to run an internal braking setup? I never considered that being possible.

There is no foot brake. The lathe is way too old for that.

I did not explain VFD braking clearly.

A VFD has a built in braking function what will electronically slow down the motor. This is a programmable function on all the VFD's I have used.

Many/most VFD's allow you to add a big external resistor to the VFD which dissipates the electromotive force from the motor FASTER than the built in braking resistor.

The fastest I can program the Hitachi VFD on my SB 13 lathe with a decent sized part in the chuck to bring the motor/spindle to a stop is 2 seconds. If I try to program the Hitachi to stop the motor/spindle faster than 2 seconds the VFD will throw an error code because it can't dissipate that much energy from the motor/spindle any faster than 2 seconds. If I add an EXTERNAL BRAKING RESISTOR to the VFD and program the VFD to use the external braking resistor to dissipate the motor/spindle energy I should be able to program the VFD to stop the motor/spindle in .5 seconds or less without throwing any errors.

Adding the external braking resistor to my Hitachi VFD was just a matter of connecting the two resistor leads to the wiring block on the VFD. Configuring the Hitachi VFD to use the external braking resistor is a combination of more than a dozen parameters. I haven't figure out the proper combination of parameter settings on my Hitachi VFD to enable the external braking resistors. The couple times I tried to do this I had to factory reset the Hitachi VFD and reprogram all the non external braking resistor parameters.

Does this make more sense?

P.S. I tried setting the 19 parameters listed in this post to enable the external braking resistor on my Hitachi... I did something wrong because they didn't work for me:

Hitachi wj200 & braking resistor...need help!

Does anyone have this vfd with a resistor installed? I am having trouble with the settings, and the manual is not the easiest to follow. Just thought I would try here first before I called hitachi directly. sent from my hand held hickymajig

www.hobby-machinist.com

Here is an example of an external braking resistor. https://www.amazon.com/Braking-Resistor-1000w-Accessory-Inverter/dp/B0791CLF8W/ref=sr_1_3?sr=8-3
These resistors are roughly a foot long.

 

[Firstram]

Do you think that a lathe from the 20's or 30's will be able to run an internal braking setup? I never considered that being possible.

There is no foot brake. The lathe is way too old for that.

If you have a threaded spindle, you don't want to set up braking!

 

[Batmanacw]

I did not explain VFD braking clearly.

A VFD has a built in braking function what will electronically slow down the motor. This is a programmable function on all the VFD's I have used.

Many/most VFD's allow you to add a big external resistor to the VFD which dissipates the electromotive force from the motor FASTER than the built in braking resistor.

The fastest I can program the Hitachi VFD on my SB 13 lathe with a decent sized part in the chuck to bring the motor/spindle to a stop is 2 seconds. If I try to program the Hitachi to stop the motor/spindle faster than 2 seconds the VFD will throw an error code because it can't dissipate that much energy from the motor/spindle any faster than 2 seconds. If I add an EXTERNAL BRAKING RESISTOR to the VFD and program the VFD to use the external braking resistor to dissipate the motor/spindle energy I should be able to program the VFD to stop the motor/spindle in .5 seconds or less without throwing any errors.

Adding the external braking resistor to my Hitachi VFD was just a matter of connecting the two resistor leads to the wiring block on the VFD. Configuring the Hitachi VFD to use the external braking resistor is a combination of more than a dozen parameters. I haven't figure out the proper combination of parameter settings on my Hitachi VFD to enable the external braking resistors. The couple times I tried to do this I had to factory reset the Hitachi VFD and reprogram all the non external braking resistor parameters.

Does this make more sense?

P.S. I tried setting the 19 parameters listed in this post to enable the external braking resistor on my Hitachi... I did something wrong because they didn't work for me:

Hitachi wj200 & braking resistor...need help!

Does anyone have this vfd with a resistor installed? I am having trouble with the settings, and the manual is not the easiest to follow. Just thought I would try here first before I called hitachi directly. sent from my hand held hickymajig

www.hobby-machinist.com

Here is an example of an external braking resistor. https://www.amazon.com/Braking-Resistor-1000w-Accessory-Inverter/dp/B0791CLF8W/ref=sr_1_3?sr=8-3
These resistors are roughly a foot long.

So I can program my vfd to gently slow down my lathe within a few seconds without unscrewing my chuck.....lol

 

[Batmanacw]

On Amazon it's only $15 more for 12-3 so I'll wire up a spare outlet for the eventual dro and light.

 

[rabler]

The maximum amp draw from the vfd is 13 amps. The motor will draw 10 fla. I'm not seeing how a 20 amp circuit isn't enough.

I believe you're intending to power the VFD single phase? A three phase motor drawing 10 FLA is drawing a sustained 10 amps on each of three wires. When supplied by 2 wires (single phase), the equivalent power is supplied by approximately 17.3 amps. A VFD with a maximum of 13 amps input on single phase cannot sustain 10 amps on three phase to the motor. Cheap import VFDs often falsely claim otherwise (and my 120V vacuum cleaner claims peak 5HP). Since VFDs are not 100% efficient, you'd need 18+ amps single phase to sustain 10amps. Sizing VFDs by HP is an approximation. VFDs are really sized by output current to match the motor FLA.

An electrical motor may significantly exceed FLA briefly on startup, or briefly under heavy load. If you go strictly by electrical code, circuits aren't suppose to be loaded to 100% capacity especially for loads like motors where a brief high startup current occurs. So a 20A circuit isn't suitable, and 30A is the next step up.

All that said, I run a 3HP lathe w/ VFD on a 20a single phase circuit and have never blown the breaker. I do have the VFD programmed to ramp up somewhat slowly to avoid high startup current, and to allow the RPM to slow down when the current draw gets too high. So I'm potentially sacrificing some performance by not using a 30a circuit.

 

[Flyinfool]

I don't think this statement is a "fair" representation of what most decent VFD do. Inductive motors are just that, inductive. Hence, this means that they have a lot of inductance. Also, a good VFD stores the line rectified energy on high voltage capacitors. The circuit combination of the capacitors and the motor inductance, means that a step function of voltage does not produce a step function of current nor voltage. PWM of modern VFDs should break the sine wave period into a bunch of increments of time, pulses, each of which is smoothed by inductance/capacitance to approximate a sine wave at the programed output frequency and voltage. When you want to run the motor at low RPM both the voltage and the frequency is changed. My Hitachi WJ-200-022SF will put out upper frequencies of around 400 Hz. This means that to work properly the PWM frequency must be considerably faster. In fact it is in the kHz range: From the manual:


Dave L.

The internal caps do help a lot. The inductance of the motor will help smooth the current spikes but not the voltage spikes. The windings can still see the spikes.
The better VFDs do have the caps and that will help smooth things out. Not all VFDs have the big caps. At work we let the magic blue smoke out of a bunch of motors before we learned this. Even on $4000+ inverters that ran and coordinated 4 separate 3HP, 3PH motors in a piece of equipment. (Input power was 74VDC, I don't remember the number but it was a LOT of amps input I remember the inrush when it all started was over 1,000 amps.) Once we started to specify inverter duty motors never cooked another one. This is a real thing. It does not affect all motors the same it does not affect all inverters the same. It depends on how the motor and inverter were built.

Today I don't know if you can even buy an non inverter duty motor, they are all just built that way. That is why you seldom see inverter duty in the specs anymore. But when dealing with a old motor and an inexpensive VFD, it is something to consider.

In this case he has a 220/440 motor so there will be no problem with this.