PK546PMA/CRD5107P RUN and STANDSTILL current

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PK546PMA/CRD5107P RUN and STANDSTILL current

Post by rikeda » Thu Oct 29, 2015 3:52 am

I set up a PK546PMA motor and a CRD5107P driver (actually I am not really sure if this is the right model, I followed the pictures in the manual and the 07P white square marked in the bottom of circuit) and I am having a overshooting situation when moving the motor. I am sure it isn't a mechanical issue and I am pulsing at 250Hz. When stopped I can easily move the motor manually without increasing the current. So I tried to calibrate the run and standstill current as described in manuals and need a little help to understand the results.
The ammeter is measuring what it seems to be an alternate current and not DC (it was oscilating, couldn't say if it is a sine wave though). Is this right?
As my power source shows the current used, I could verify how much the driver was consuming (higher than transmitted to the motor) and did both runand standstill pot calibration. I could achieve max current in RUN mode at 1.2A, which would be less than 0.6A/phase. But STANDSTILL stopped at max of 0.55A, or less than 0.27A/phase. This could be less than 1/3 of what would be suitable for this motor. Is this the max current I would reach?
Thanks in Advance

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Re: PK546PMA/CRD5107P RUN and STANDSTILL current

Post by om_tech_support_JT » Tue Nov 10, 2015 6:42 pm

Hi Rikeda,

Overshooting of a stepper motor can occur if the motor does not generate enough torque to decelerate the motor to a stop. This happens when deceleration is set too fast. We could slow down the deceleration to see if that helps. If the # of steps programmed is higher than it should be, it would also overshoot.

Is this overshooting every single time by the same distance?

The current draw of the CRD5107P driver is directly related to the RUN/STOP potentiometers on the driver and if the motor is at rest or moving. When the motor is moving, the current draw is based on the RUN setting. When the motor is resting at standstill, the current draw is based on the STOP setting. Our drivers reduce current at standstill to allow the motor to cool during rest.

I would need to ask some questions to understand the situation better.

1. When the motor is at standstill, the STOP current is defaulted to 50% of the RUN current. The RUN current is at max setting when we ship the driver. If you haven't changed any settings, it's difficult to believe that you can easily move the motor manually if the motor and driver are powered. If the All Windings Off input is turned ON, then it disables the motor excitation. At that time, you can move the motor easily by hand. Is this what's happening?

2. Where are you measuring with the ammeter? Between the motor and driver, or between driver and power supply? The current between the motor and driver cannot be easily measured. The input current to the driver can be easily measured but it will fluctuate depending on what the motor is doing at the time. Max current draw for the CRD5107P driver should be 1.4 A as stated in its specifications.

The driver will require more input current than the motor's rated current. 1.2A current draw from the power supply does not mean it's 0.6 A/ph for the motor. The PK546PMA motor + CRD5107 driver together should require about 1.4 A at max RUN/STOP settings, then the driver would send 0.75 A/ph to the motor which is what the motor is rated for.

Hope this helps.

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Re: PK546PMA/CRD5107P RUN and STANDSTILL current

Post by aldoned » Fri Jun 17, 2016 9:00 pm

Thanks for the info

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