assistance with inverter duty motors

[bombero]

Our Company electricty is provided by a 35KW Generator and we installed 5 4000 watts Xantrax Inverters (model # SW4024) and 10 1600AH batteries but the problem is that whenever the generator shuts off and we are running on inverters the lights on our 12 Hunter Fans flicker and eventually turn off. The Fan itself also slows down at first and then start rotating faster after a bit. Apparently these fans are not manufactured with inverter duty motors.
Any suggestion on how to solve this problem?

 

[jraef]

It probably has nothing to do with the motors. Inverter duty would mean only that the motor can withstand the additional stresses of being run from an inverter, and that is only applicable to 3 phase motors anyway. If you are speaking of Hunter ceiling mounted circulation fans with light fixtures, they are 1 phase shaded pole motors, there is no such thing as "inverter duty" for those.

More likely it is an incompatability between some sort of electronic controller built-in to the fans and lights with the output ofyour inverters. Many of them are SCR phase angle controllers that simply reduce the voltage, and phase angle controllers are generally difficult to power up from a PWM source unless there is a lot of filtering in the inverter. Cheaper inverters often do not include sine wave filtering.

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[bombero]

Thanks jraef. You are right. They are Hunter Fans. so what do you recommend we do to fix it? We can't just get rid of fans that cost us thousands of dollars.

 

[jraef]

Well looking at the specs on that inverter it is not a PWM output, it is a step wave that is supposely "utility grade", whatever that means. That may be even worse in terms of affecting your fan controllers. I would contact Hunter and give them the specs on the inverter to see if they suggest anything since they will know what their controller can put up with. I'd also call Xantrex as well.

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[bombero]

ok thanks again. will see what comes of it. anymore suggestion let me know.