Stepper Motor Clarifications

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essenceindia
Posts: 28
Joined: Thu Nov 16, 2017 7:46 am

Stepper Motor Clarifications

Postby essenceindia » Mon Jan 29, 2018 3:28 am

Hi !!
Good Day !!

We have purchase 2-phase stepper motor PKP264U20A-SG36-L with CVD223-K driver. Below is the speed-torque curve of the existing motor:
https://catalog.orientalmotor.com/Asset ... sg36-l.jpg

Now the customer is looking for another new model with strongly recommended to achieving 100 deg. / sec (@ 2 khz / more starting frequency).

So, could you please suggest other motor & driver combination, which supports starting frequency of 2 khz & above to full fill customer requirement and proceed further in this matter.

Thanking you & Best Regards,

om_tech_support_JS
Posts: 192
Joined: Tue May 10, 2016 4:48 pm

Re: Stepper Motor Clarifications

Postby om_tech_support_JS » Mon Jan 29, 2018 2:25 pm

Hi essenceindia,

In regards to this post, the fs (starting frequency) is the frequency at which the motor can start and stop instantaneously. However, it is not the max operating speed; the max speed that this system can operate at is 10 kHz. Therefore, if they are looking to operate at 100 degrees/sec (2 kHz), then they could still use the current PKP264U20A-SG36-L stepper motor with the CVD223-K driver. They would just need to start at the slower frequency and then accelerate up to the 100 degrees per second.


Otherwise, why do they require the 100 degree/sec starting speed? Is there a specific motion profile that they need to achieve?

essenceindia
Posts: 28
Joined: Thu Nov 16, 2017 7:46 am

Re: Stepper Motor Clarifications

Postby essenceindia » Tue Jan 30, 2018 4:36 am

Hi !!
As per our requirement, the motor should not run beyond 360 deg and it should rotate only one cycle with starting frequency of 2 Khz.
As you said, if we are running the motor continuously it’s ok but we will run the motor only one complete cycle from 0 to 360 deg. When we set speed: 100 deg/sec, the motor should start @ 2 khz and rotates one complete cycle (from 0 deg to 360 deg) and the waveform should be linear(straight line) from start to end of the cycle not gradual increase.

If we start the motor from lower frequency to 2 khz, the waveform will not be linear and timing mismatch will come when we calculate 100 deg /sec.

Also please suggest us alternate models equivalent above parameters to proceed further in this matter.

essenceindia
Posts: 28
Joined: Thu Nov 16, 2017 7:46 am

Re: Stepper Motor Clarifications

Postby essenceindia » Wed Jan 31, 2018 5:44 am

with continuation to our Yesterday's message, please suggest us right suitable model with High Starting Frequency @ 100 deg/sec.
The pulling torque is around 1.0 Nm, please look into this and do the favorable in this regard.

om_tech_support_JS
Posts: 192
Joined: Tue May 10, 2016 4:48 pm

Re: Stepper Motor Clarifications

Postby om_tech_support_JS » Wed Jan 31, 2018 3:34 pm

Hi essenceindia,

In regards to your posts, setting the starting frequency {fs} to a higher value requires more acceleration torque. For this reason, the speed-torque curve shows the maximum starting frequency (unloaded) since there is only so much torque that this motor can generate. It should also be noted that the maximum starting frequency of a given stepper motor of the same frame size will be roughly the same. Therefore, there is unfortunately no replacement option that will have a higher starting frequency.

In addition to increasing the acceleration torque, a high starting frequency also causes more vibration at the beginning and at the settling of the motion. In generally, it is recommend to use a trapezoidal motion profile for smoother operation. To help calculate the required operating frequency for a trapezoidal motion profile, I have included the following equation:

Operating Frequency Formula.png
Operating Frequency Formula.png (3.59 KiB) Viewed 688 times

where:
f2: is the operating frequency
A: is the total number of steps (for your system, it takes 7200 steps to go 1 revolution).
f1: is the starting frequency
tt: is the total time
ta: is the acceleration time, which is usually calculated as ta = tt*0.25 (or 25% of the total time)


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