Demetrio Urrea

Powerflex 400 25HP wird amp behavior

3 posts in this topic

ello I have a powerflex 400 of 25HP for a 60amp 25HP motor, the motor have a belt that move the clarifier of milk. It is a process that requires strength to move.

So I try with the motor without the clarifier the vdf works well with a constant amp of 12 to the max of 50hz that is set up with a ramp of 600 sec.

Then I try with the belt that move the clarifier... The vdf start the ramp with a wird amp behavior like 10 sec 100 amp and then 13 amp for 10 sec.

When it gets to 50hz (the max) it starts the same behavior 13 amp when it reach the max RPM and when it decrease a little bit it gets 100 amp to get to the max RPM again.

In this vdf powerflex 400 I didn't see the % of torque options that the last one Fuji had.

Someone told me that powerflex 400 is not for power processed, they are focus in pumps and blowers more alike, and that I need a vdf vectorial like a powerflex 725.

What do you think...

PD: as the 100 amp is like 10 sec the protections dont show up.

PD: I made a try with water and hot water, in that point with the max hz  (and 6800rpm) when the hot water start to flow the amp gets constant in 75 amp, but the motor dosnt get to the 6800 rpm again it just keep trying in 6700rpm and it mantains the 75amp triggering the motor protection for overload.

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You were informed correctly; the PF400 is primarily designed for pumps and fans. There is no PF725 that I'm aware of. I think you might have meant to type 755. There is a PF525 but it is only rated up to 30HP.

You mentioned that you were looking for torque options. The PF755 does have almost 20 torque parameters, while the PF400 only has one; Parameter 13 "Torque Current", which is a read-only parameter which displays the torque portion of the output current.

It is important to note that with any AC motor there is an inverse relationship between torque and speed. Whether or not your system is set up as a torque (rather than speed) follower, it makes sense that you'd see amp fluctuations with changes in speed or load demand. This might be worse in the 400, which was designed to run best on a modified V/Hz curve for pumps and fans. 

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1 hour ago, ElectronGuru said:

You were informed correctly; the PF400 is primarily designed for pumps and fans. There is no PF725 that I'm aware of. I think you might have meant to type 755. There is a PF525 but it is only rated up to 30HP.

You mentioned that you were looking for torque options. The PF755 does have almost 20 torque parameters, while the PF400 only has one; Parameter 13 "Torque Current", which is a read-only parameter which displays the torque portion of the output current.

It is important to note that with any AC motor there is an inverse relationship between torque and speed. Whether or not your system is set up as a torque (rather than speed) follower, it makes sense that you'd see amp fluctuations with changes in speed or load demand. This might be worse in the 400, which was designed to run best on a modified V/Hz curve for pumps and fans. 

750 Series i meant, Well Tomorrow i should call an external for my shame, but i will make some changes in a last try to make an effort, we dont have another VFD and neither the resources to buy another in short terms, So ill try with compensation, boost and expect to get at least a little bit more efficient. But its the first time that i see a motor with a 100 amp to movilize and 13 amp to "rest" its something very odd.

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