ZETA Motor Power Spec Question
18 Feb 2014 11:47 #43933
by steptool
ZETA Motor Power Spec Question was created by steptool
Greetings,
I have been given some motors that are actually speced to go with specific drive made by Parker (Compumotor)
These are nema 23 motors and I have several types in hand. I am trying to sort out the specs to do the math for proper power requirements but I am confused by the actual motor spec sheet. When I do the math according to the wonderful information that I have found here, Gecko drive's web site and others it just doesnt seem to add up and I'm sure its just because of my understanding.
Here is the actual link for the spec sheet:
www.motionusa-store.com.s3-website-us-ea...ES-ZETA-S-Motors.pdf
Below is a condensed version that I just edited for review here:
Specifications:
Parker Hannifin Corporation
Compumotor Division
compumotor.com
Automation
ES Series Stepper
Motor Specifications
Size 23
Size 23
Parameters
ES21B (ZETA 57-51) (THIS IS ONE OF MY MODEL NUMBERS)
Static torque oz-in 117 (N-m) (0.8)
Rotor inertia oz-in2 0.546 (kg-m2x 10–2) (9.998)
Phase Inductance
Series 17.37
Parallel 4.34
Drive Bus Voltage VDC 170 (THIS IS THE NUMBER THAT REALLY IS THROWING ME)
Detent Torque oz-in 1.4 (N-m) (0.01)
Bearings Thrust load lb 25 (kg) (11.3)
Radial load lb 15 (kg) (6.8)
End play in 0.005
Reversing load(cm) (0.013)
Equal to 1 lb
Radial play in 0.0008
Per 0.5 lb load (cm) (0.002)
Weight (net)Motor+Cable lb 1.6 +Connector (kg) (0.7)
Motor Cable Wire size AWG 24 (mm 2) (0.25)
ZETA Apk (Arms)
Series 1.76 (1.24)
Parallel 3.5 (2.48) (I WOULD BE USING THESE IN PARALLEL)
On just a quick bench test I hooked this one up to a Gecko 201 set at 2A an 24VDC (Both also set from a benchtop power supply) just to see work...Seem to run well, sound good, but this of course was with no load.
So if E=IR then E=3.5(at peak) * 3.2 (measured Phase resistance) = 11.2VDC
So even if I multiply that times 4 from gecko's worksheet that still falls way short of 170VDC
And even if the 170VDC is just "MAX the motor could handle" ......who in the word would actually run it that high???
And when I tried to figure it out by using inductance I got really confused. (be nice, im new....lol)
So I was hoping with all the great minds I have read from here, that someone might be able to point out my misunderstanding and I could properly figure out the other motors and sucessfully put together a system powered correctly without blowing anything up.......
Thanks,
gman
I have been given some motors that are actually speced to go with specific drive made by Parker (Compumotor)
These are nema 23 motors and I have several types in hand. I am trying to sort out the specs to do the math for proper power requirements but I am confused by the actual motor spec sheet. When I do the math according to the wonderful information that I have found here, Gecko drive's web site and others it just doesnt seem to add up and I'm sure its just because of my understanding.
Here is the actual link for the spec sheet:
www.motionusa-store.com.s3-website-us-ea...ES-ZETA-S-Motors.pdf
Below is a condensed version that I just edited for review here:
Specifications:
Parker Hannifin Corporation
Compumotor Division
compumotor.com
Automation
ES Series Stepper
Motor Specifications
Size 23
Size 23
Parameters
ES21B (ZETA 57-51) (THIS IS ONE OF MY MODEL NUMBERS)
Static torque oz-in 117 (N-m) (0.8)
Rotor inertia oz-in2 0.546 (kg-m2x 10–2) (9.998)
Phase Inductance
Series 17.37
Parallel 4.34
Drive Bus Voltage VDC 170 (THIS IS THE NUMBER THAT REALLY IS THROWING ME)
Detent Torque oz-in 1.4 (N-m) (0.01)
Bearings Thrust load lb 25 (kg) (11.3)
Radial load lb 15 (kg) (6.8)
End play in 0.005
Reversing load(cm) (0.013)
Equal to 1 lb
Radial play in 0.0008
Per 0.5 lb load (cm) (0.002)
Weight (net)Motor+Cable lb 1.6 +Connector (kg) (0.7)
Motor Cable Wire size AWG 24 (mm 2) (0.25)
ZETA Apk (Arms)
Series 1.76 (1.24)
Parallel 3.5 (2.48) (I WOULD BE USING THESE IN PARALLEL)
On just a quick bench test I hooked this one up to a Gecko 201 set at 2A an 24VDC (Both also set from a benchtop power supply) just to see work...Seem to run well, sound good, but this of course was with no load.
So if E=IR then E=3.5(at peak) * 3.2 (measured Phase resistance) = 11.2VDC
So even if I multiply that times 4 from gecko's worksheet that still falls way short of 170VDC
And even if the 170VDC is just "MAX the motor could handle" ......who in the word would actually run it that high???
And when I tried to figure it out by using inductance I got really confused. (be nice, im new....lol)
So I was hoping with all the great minds I have read from here, that someone might be able to point out my misunderstanding and I could properly figure out the other motors and sucessfully put together a system powered correctly without blowing anything up.......
Thanks,
gman
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18 Feb 2014 13:02 #43934
by cmorley
Replied by cmorley on topic ZETA Motor Power Spec Question
These motors ate pretty special and designed for their drives which output 170volts.
IIRC they are low inductance. They are made so they can rotate very fast 50rms or 3000 rpm.
There is info how to use them with other drives in the manual.
Chris
IIRC they are low inductance. They are made so they can rotate very fast 50rms or 3000 rpm.
There is info how to use them with other drives in the manual.
Chris
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25 Feb 2014 00:41 #44135
by andypugh
As the step rate increases then the inductance of the motors becomes more and more relevant. The rate of change of current is huge as the phases are changed through the step pattern. The back-emf is proportional to the rate of change of current x inductance. The voltage that the windings "see" is the supply voltage - the back-emf. At some point there simply isn't enough voltage to push any current through the windings, and there is then no torque to turn the motor.
I am being simplistic.
With a stepper motor the current is limited by the drive, not by the motor dc resistance, so it is safe to use very high voltages if the drive can handle it, and if the motor insulation is good enough.
High voltage stepper drives are fairly readily available, for example www.zappautomation.co.uk/en/digital-step...ers/319-2m1180n.html
This type of drive connects directly to mains voltage without a PSU.
However, if you don't need the speed, then there is no need to run the motors at the voltage they are capable of. The actual low-speed torque will be exactly the same at any supply voltage, it will just drop off faster with speed at the lower voltage.
Replied by andypugh on topic ZETA Motor Power Spec Question
So even if I multiply that times 4 from gecko's worksheet that still falls way short of 170VDC
And even if the 170VDC is just "MAX the motor could handle" ......who in the word would actually run it that high???
As the step rate increases then the inductance of the motors becomes more and more relevant. The rate of change of current is huge as the phases are changed through the step pattern. The back-emf is proportional to the rate of change of current x inductance. The voltage that the windings "see" is the supply voltage - the back-emf. At some point there simply isn't enough voltage to push any current through the windings, and there is then no torque to turn the motor.
I am being simplistic.
With a stepper motor the current is limited by the drive, not by the motor dc resistance, so it is safe to use very high voltages if the drive can handle it, and if the motor insulation is good enough.
High voltage stepper drives are fairly readily available, for example www.zappautomation.co.uk/en/digital-step...ers/319-2m1180n.html
This type of drive connects directly to mains voltage without a PSU.
However, if you don't need the speed, then there is no need to run the motors at the voltage they are capable of. The actual low-speed torque will be exactly the same at any supply voltage, it will just drop off faster with speed at the lower voltage.
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