Unipolar / Bipolar Connections for 2-Phase Stepper Motors

Connections

Resistance

(Ohms)

Inductance

(mH)

Current

(A)

Voltage

(V)

Holding Torque

(oz-in)

Unipolar

Same as Catalog

Same as Catalog

Same as Catalog

Same as Catalog

Same as Catalog

Bipolar Series

Catalog X 2

Catalog X 4

Catalog X 0.707

Catalog X 1.414

Catalog X 1.414

Bipolar Half Coil

Same as Catalog

Same as Catalog

Same as Catalog

Same as Catalog

Same as Catalog

Bipolar Parallel

Catalog X 0.5

Same as Catalog

Catalog X 1.414

Catalog X 0.707

Catalog X 1.414

Customer's Driver

Motor Choices

What to Do

How to Do It

End Result

Unipolar

(6 Leads)

6 Lead Motor

Use as is

Unipolar

6 Leads

8 Lead Motor

Convert to

Unipolar

Tie yellow and orange together and use AND

Tie white and brown together and use

6 Leads

Bipolar

(4 Leads)

6 Lead Motor

Convert to Series

Tape off yellow and white leads and don't use

4 Leads

Convert to

Half Coil

Tape off black and red leads OR

4 Leads

Tape off green and blue leads

8 Lead Motor

Convert to

Series

Connect yellow and orange and tape off AND

Connect white and brown and tape off

4 Leads

Convert to

Parallel

Tie black and orange together AND

Tie yellow and green together AND

Tie red and brown together AND

Tie white and blue together

4 Leads

Convert to

Half Coil

Tape off black, yellow, red, and white OR

4 Leads

Tape off orange, green, brown, and blue

Unipolar and Bipolar Half Coil, because we're using less turns, doesn't give us great low speed torque, but because of the low inductance, holds the torque out to high speeds.

Bipolar Series uses the full coil so it gives very good low speed torque. But because of the high inductance, the torque drops off rapidly.

Bipolar Parallel also uses the full coil so it gives good low speed performance. And its low inductance allows the torque to be held out to high speeds. But remember, we must increase current by 40% to get those advantages.