Flux Vector Drive - Vector Duty Motor

[W@ttson]

Hello,

Just checking to see if anyone sees any issues with the following:

Want to have an acceptance criteria for a Flux vector drive and vector duty, 1000:1 TENV motor.

In the application there will need to be moments where an overload of 150% is needed for about 30 seconds or so. I want to have the motor drive system tested at 150% FLT for 30 seconds at 0 RPM (what if I push it out to 1 min?) (the drive is can handle 150% for 1 min and is oversized so it can provide this no problem). Is there any concern on heating within the motor for that short duration of overload? Since it is a 1000:1 motor I believe that will help things along. Motor will have H insulation.

Thanks

 

[Besoeker]

Hello,

Just checking to see if anyone sees any issues with the following:

Want to have an acceptance criteria for a Flux vector drive and vector duty, 1000:1 TENV motor.

In the application there will need to be moments where an overload of 150% is needed for about 30 seconds or so. I want to have the motor drive system tested at 150% FLT for 30 seconds at 0 RPM (what if I push it out to 1 min?) (the drive is can handle 150% for 1 min and is oversized so it can provide this no problem). Is there any concern on heating within the motor for that short duration of overload? Since it is a 1000:1 motor I believe that will help things along. Motor will have H insulation.

Thanks

The Non-Ventillated may be an issue over that speed range. Where we have used drives over a wide speed range we had seperate ventilation

 

[W@ttson]

It will normally be operating at base speed but at starting we need a lot of torque. The environment is no very friendly which is why the TENV is used. I think since it is rated for that speed range and for the short duration it should be OK for the testing (even though the speed range guarantees 100% rated torque and not 150%).

The Non-Ventillated may be an issue over that speed range. Where we have used drives over a wide speed range we had seperate ventilation

 

[Besoeker]

It will normally be operating at base speed but at starting we need a lot of torque. The environment is no very friendly which is why the TENV is used. I think since it is rated for that speed range and for the short duration it should be OK for the testing (even though the speed range guarantees 100% rated torque and not 150%).

I don't know if this any use to you but used water cooling when the environment required the motor to be totally unclosed.
We also used it on our high speed (25,000 rpm) motors for machine tool applications. At those sort of speeds, a shaft mounted fan is not a practical proposition.

 

[Jraef]

For the most part, quality VFDs that would offer you true Flux Vector Control (which you need for Full Torque at Zero Speed) are going to be offered in a "Heavy Duty" or "Constant Torque" specification, which means it will be capable of 150% overload current for 60 seconds. That's not an official spec requirement, it's one that the market has standardized on, so write it out to be sure to protect yourself from the bottom feeders. As to the motor, a typical NEMA designed motor will have an OL curve based on the I²t model, and good mfrs will make sure the thermal damage curve is well below that. If you plot 150A on a Class 10 I²t trip curve, you cross it at about 60 seconds as well. So 30 seconds should be no problem for either device.

PS: One thing to be careful of, TENV motors with a 1000:1 speed range are going to stop at around 100HP (you didn't say what your HP is). They are also physically bigger than standard motors or TEBC versions.