Another vfd question

[twstoerzinger]

I second what Cody is saying. Load reactors are only required when the run between the VFD and to motor gets long (50 ft or greater).
Terry S.

 

[Rangerjoe2]

I know it's not required for my application, but I'm going to try one of mte 5% impedance load reactors. My desire will be to smooth the sin wave and allow me to lower the carrier wave freq. on my vfd. That will allow the motor to run cooler and more efficiently.

 

[strantor]

I know it's not required for my application, but I'm going to try one of mte 5% impedance load reactors. My desire will be to smooth the sin wave and allow me to lower the carrier wave freq. on my vfd. That will allow the motor to run cooler and more efficiently.

Does your VFD log power consumption? I suspect that your reactor won't pay for itself, but it is something that I have always been curious about. Since you've already made the decision to go forward with it, it would be interesting to compare the numbers before installation and after.

 

[British Steel]

I know it's not required for my application, but I'm going to try one of mte 5% impedance load reactors. My desire will be to smooth the sin wave and allow me to lower the carrier wave freq. on my vfd. That will allow the motor to run cooler and more efficiently.

Another plus with load reactors is the reduction of speed of voltage rise applied to the motor windings - this makes a major difference to the stress on the insulation, which can be important on older non-VFD rated motors which aren't rated for 700v+ with microsecond rise times as delivered by 400v class VFDs.

You do *lose* that 5% as loss in the load reactors, when considering the sine-wave in the load, but the loss at higher frequencies (eg several KHz switching) is much higher, effectively blocking the fast rising/falling edges that can cause insulation breakdown. The windings won't whine as loudly, either!