Should a VFD make a motor run unevenly?

Re: Should a VFD make a motor run unevenly?

john lucas

I am not sharp with electric motors but have installed 2 VFD's. both work perfectly and run smooth. There are so many variables that can be programmed into the VFD. This is so they can be used with a lot of different motors and applications. I wonder if there is a setting somewhere that needs to be changed to run properly with your motor. Most of what I read when setting mine up was over my head and I didn't touch them.

Re: Should a VFD make a motor run unevenly?

Henry Higginbotham

Thank you, John. The issue was there with the factory default settings and didn't change even after I monkeyed with acceleration and deceleration times and a few other variables. I may try contacting Teco directly.

you may have purchased too small of VFD *LINK*

Dick Coers

"For single-phase input, it is important to take a few more things into consideration. If the load is 3 HP (roughly a 230 VAC motor with an FLA below 10 amps) or below it is likely that we have a drive built for single phase input in stock for you to hook up and run with. If your needs are greater than 3 HP, then it is possible to use a drive built for three phase input, however the drive must be properly sized for your application. This is because the diode bridge is meant to carry current through all three legs. Thus, the rule of thumb for sizing the single phase input on a three-phase drive is to use a VFD rated for 2 times the FLA of the motor. For example if your motor is a 10 HP motor with a FLA of 28 amps, then you would need to select a VFD with an amp rating of 56 amps which ends up being around 20 HP"


https://www.vfds.com/blog/vfd-buying-guide

Re: you may have purchased too small of VFD

Walt

If I read that web site info correctly, they're talking about running a 3 phase input VFD on single phase. Only 2 of the 3 legs would have current.