RE: [CAD_CAM_EDM_DRO] Re: QUESTION ABOUT SERIES OR PARALLEL ON STEPPER MOTORS - ref post 52721

Tim:

I guess I can use another power supply which has a 105 volt tap on the
primary. It has two 12 volt secondary windings which I can place in series.
It's currently giving off 16.5 volts DV after the capacitor from each
winding. If I move the tap from the 115 v to the 105 volt tap on the
primary and put the two secondary coils in series, I can get about 36 volts
DC. The transformer is about half the size of a shoe box, so I assume it
can handle the load (?). Do you know if I have to change the capacitor? (it
currently has one for each of the secondary outputs (which are currently
wired in parallel with each other). Should I change to the capacitor which
is currently across the 130 volt DC supply (bridged by a 1k ohm resistor)?

I've got an 8 terminal stepper. I've got wiring diagrams for series and
parallel (and a wiring diagram of a 6 terminal stepper as half coil). What
is the proper way to hook an 8 terminal stepper as half coil?

Thanks again for all the help.

Jeff


-----Original Message-----
From: Tim Goldstein [mailto:timg@...]
Sent: Saturday, February 15, 2003 3:32 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: RE: [CAD_CAM_EDM_DRO] Re: QUESTION ABOUT SERIES OR PARALLEL ON
STEPPER MOTORS - ref post 52721


At 25X over voltage it will run quite hot. At more voltage it will run even
hotter. The 25X value is empirically derived as the general upper limit
based upon the motor heating. It is not a absolute limit, but you have to
consider the potential you will damage the motor by over heating it.
Personally I find that even at 25X the motors run hotter than I like. Not
that it is beyond the spec, but I don't like having the motors at a
temperature that will cook meat. If it was my machine I would likely set it
up with 36 - 48 v and wire it as half coil. Series will seriously limit your
max RPM and parallel takes a lot of amps. Half coil cuts the amps while
giving almost all the speed of parallel.

Tim
[Denver, CO]
Sherline products at Deep Discount
Mach1 & DeskCNC with credit card ordering www.KTMarketing.com/Sherline Now
selling Visual Mill

> -----Original Message-----

> The nameplate on his motor rates it at 2.1 volts and 9.2 amperes.
>
> Is it OK to drive this at 62 volts DC? I read that the
> voltage should not exceed 25 times the rated voltage which
> would be 52.5 volts.
>
> Since the application is a direct connection to the XY and Z
> axis of a Bridgeport Milling machine, (and since the drive
> tops out at 8 amperes) is it better to try running it at 8
> amperes in parallel or at 4.5 amperes in series?
>
> Again, thanks much for all your help.
>
> Jeff

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