Simple motor wiring question 1

[brewersean]

Hi,

I have a very basic knowledge of electricity and motors, but have run into a bit of a bind.

I have a single phase 16A 22OV power supply for a 3 phase motor (

http://www.cnyuy.com/sanitary-centrifugal-pump/yuy-l-sanitary-centrifugal-pump)

I am trying to install a VFD on.

I have two problems, the pump direction is backward (regardless of switching any of the WVU wires) and after about 42hz the VFD trips on ''Short Circuit/Current overload/Power Module protection''

I am lacking the understanding of what is actually happening when converting single to 3 phase, whether the capacitor is necessary or in the way, etc.

Can anyone shed any light on this?

Thanks!
Sean

 

[moa1]

Last shot...try this at your own risk. Good luck

 

[brewersean]

What about if I install a 3 pole double throw switch that will allow me to start the motor without the VFD and then switch to the VFD once the motor is running, removing the starting capacitor from the circuit in the VFD mode?

 

[jraef]

That's a lot of effort with no guarantee it will work. I would either change the motor to 3 phase (if possible) or give up on the speed control. I know that some of these Chinesium drives CLAIM to be able to handle Capacitor Start single phase motors, but from my experiments on that a few years ago, its a race to see if the VFD transistors fail before the capacitor does. The charging current of the cap looks like a short circuit to the transistors, meaning a high dI/dt (rapid rise in current) that can damage the transistors, while at the same time the capacitor over heats as it tries to absorb the harmonics created by the PWM coming from the VFD and swells to the point of failure.


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