Power Flex 525

[Good Electric 307]

I have a 5 Hp powerflex 525 that I am having trouble with an overcurrent fault. I am new to drives and don't understand all parameters. I have a pump that is being controlled by a motor starter feeding another pump being controlled by the powerflex. When I have the first pump running and start the second pump I get an overcurrent fault. If I take the first pump out of the picture I seem to run with no problem on the second pump with the drive. Is there a parameter that needs to change assuming that pump with the drive is trying to hold back and overloading the motor? The reason for the second pump is to try to keep a constant psi (running off a transducer) to speed up and slow down the motor. This is confusing I know but this is a set up that I was thrown into and told to make it work.

 

[Engineerj22]

Just so I get this straight you have two pumps, A&B. A is started by a motor starter and runs at max speed. B is controlled by the PF525.

A feeds into B. If A is running when B is started, B will fault with overcurrent. If A isn't running, B starts just fine. Correct?

 

[joseph_e2]

One thing to try is to enable "flying start" (parameter A545) on the drive. If the first pump is running, the second pump will be rotating because of the fluid flow. That can confuse the VFD, leading to an overcurrent fault.

 

[Good Electric 307]

Engineer22 yes that is exactly right. I will try to change (A545) and see what happens as joseph_e2 has mentioned