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

[xyz]

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

 

[mksj]

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.

 

[xyz]

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"

 

[xyz]

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.

 

[xyz]

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.