2
\$\begingroup\$

I'm converting an old milling machine (Optimum F40E) machine to be driven with a VFD, and I have it working. The head is a geared head, and with correct settings (torque compensation) in the VFD I can overcome the startup torque in the gear-train when the machine is shifted into the "high speed" gear.

There is continuity between all six terminals in the terminal box on the motor.

I measured the resistance between U/V/W 1..6 and found something unexpected. The housing for the wiring doesn't contain any bus-bars, so the motor must be internally wound a specific way.

Here's the motor info plate:

enter image description here

The resistance between the terminals is as such (I measured every terminal combination explicitly, even though this is redundant)

enter image description here

Is this a star, or delta internal configuration, or is the motor damaged?

\$\endgroup\$
2
  • 1
    \$\begingroup\$ I think there's an error in your second column at the bottom. \$\endgroup\$
    – Andy aka
    Commented Jul 5, 2023 at 11:45
  • 1
    \$\begingroup\$ there is an error in "the row terminal designations" (the last one, by the looks of it), and I don't believe the value column #6, row #4 value. \$\endgroup\$
    – greybeard
    Commented Jul 5, 2023 at 17:45

1 Answer 1

Reset to default
3
\$\begingroup\$

It's a 'Dahlander' two-speed, pole-changing motor.

enter image description here

The windings are 'delta-connected' for 1400 RPM and 'double star-connected' for 2800 RPM.

\$\endgroup\$
0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.