VFD with a 3600 RPM motor 1

[JohnnieE]

I have always used VFD with 1800 RPM base speed motors. Now I have an application where I want to apply a VFD to a 3600 RPM base speed motor. Is there any problem with using a VFD on a 3600 RPM motor and running at 60HZ or less?

 

[atvargas]

JohnnieE: What kind of motor you will use?
TENV, TEFC etc.?
What are the cycles of work? as an example: 10 min work, 10 min rest or 10 min work 30 min rest? specify
What is the average freq. of work period?
What is the type of work? A pump, a mill, a hoist, a trolley? what type. Indicate

 

[dpc]

No inherent problems with 3600 rpm motors on AFDs that I am aware of.

 

[jbartos]

Suggestion: It would be prudent to go by the second posting requests on the original posting elaboration. I just would add the following question:
Do you intend to use a small fan motor for the VFD motor low speed cooling?

 

[JohnnieE]

Thanks for the help, some additional details are It is a 5HP motor, OPD housing, duty cycle would be 8 minutes on, 2 minutes off, nornmally running at 60HZ with the VFD being mainly used for acceleration and deceleration control with some occasional slow speed running, perhaps for 5 minutes every 6-8 hours. The machine is a wire rewinder. Cycle is Start, 6 second acceleration, 7-8 minutes run at full HZ, followed by a 45 second deceleration, 2 minute wait and then repeat

 

[rostislav]

JohnieE, there is no problem with VFD + 2pole motor (3600RPM), if you will run it between 25 - 50Hz. If you will go down, be carefull about overtemperature of the motor. If you will go up, the bearings lifetime will be shorter.

 

[ggianni]

If this motor is lightly loaded than 20 to 60 Hz is okay. Under 20 Hz and lightly load you could remove some "DC boost" and change the v/Hz ratio, in turn reducing the unneeded motor flux that generates extra heat. Reduce till the current starts to increase then back up some. A seperate blower mtr could be used at lower speeds or I've installed dry mill-air in the end bells( only at low speeds).
A inverter duty motor is (some are)dyn. balanced to 4000 rpm and one frame up could get you to 4600 rpm,and with the manufactures blessings. If you are using a sensor-less vfd, then your speed can drift with the load change. A 1024 ppr encoder on the mtr could be great asset for quality control at all speeds.

 

[atvargas]

JohnnieE: You can select a Yaskawa VFD. This kind of inverter will suit to your aplication very good. you can select a decelaration ramp from 1 to 60 sec and up.
Motor must be equiped with a fan (TEFC Motor Type) or if possible attach a separated fan blower.

 

[jbartos]

Suggestion. The machine rewinder may use the low rpm motor mode. Therefore, the motor temperature at low rpm should not be overlooked, and cooling properly engineered and designed.