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#1




Coil Inductance measurement, is this normal?
I bought these 86HS9801 specs
It says the coils has 4.1mH I measured the inductance between the wires & the results as follows Coil A, 3.64mH, 3.67mH, 3.71mH, 3.67mH (RedYellow) Coil B, 3.61mH, 3.46mH, 3.53mH, 3.80mH (OrangeWhite) Coil C, 3.62mH, 3.42mH, 3.56mH, 3.77mH (BrownGreen) Coil D, 3.65mH, 3.71mH, 3.72mH, 3.66mH (BlueBlack) Are they consider normal? I'm using 48Vac tranny should give about 65~66Vdc, Consider these, 32*sqrt(3.4) = 59V (lowest measured value) 32* sqrt(3.8) =62V (highest measured value) 32*sqrt(4.1) = 65V (original based on maker's spec) The motors will run 5~7 V higher then recommended voltage. Will I be in any sort of problems? Thanks in advance. Ken Last edited by KenC; Wed 18 November 2009 at 05:10.. 
#2




I don't think you will have a problem . . .
If your motors run a little bit too hot, then reduce the current setting on the drive. 
#3




Quote:

#4




Anil, I'm using a DMM to measure, not sure what frequency the use though...
Gerald, Thanks again. will have to remember keep a close monitoring on the heated motors. I am also concern that the values varies greatly between coils & motors. Is that normal? 
#5




I'm not an expert on this but i think Inductance is measured at 1Khz, rotor locked position. Anyway as Gerald said it doesn't matter here, just keep an eye and reduce voltage if motors seems overheating.

#6




The biggest variance is between the 3.42mH and 3.80mH measured values. The average value between those two is 3.61mH with a variance of 0.19mH to either side. That is only 5% . . . . . which I think is darn good!

#7




OK, inspired by gerald, I took a quick stats analysis with spreadsheet, I get standard deviation of 0.08 & a median of 3.65, that is +/2.2%. I can ask any better then that.
This is the wiring diagram I received, want to be sure that I'm doing the correct thing. stepper motor wire color.jpg For half coil, use 1) coil A(redyellow) & coil B(whiteorange)? 2) it really doesn't matter as long as we take half of each phase? 
#8




Quite correct on both points.

#9




Thank you for you reply.
Ken 
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