Intelligent Motion Systems Motion Detector User Manual

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Microstepping MForce PowerDrive Manual Revision R032008

The per phase winding inductance specified may be different than the per phase inductance seen by your MForce 
PowerDrive  driver depending on the wiring configuration used. Your calculations must allow for the actual induc-
tance that the driver will see based upon the wiring configuration.

Figure 2.3.1A shows a stepper motor in a series configuration.  In this configuration, the per phase inductance 
will be 4 times that specified.  For example: a stepping motor has a specified per phase inductance of 1.47mH.  In 
this configuration the driver will see 5.88 mH per phase.

Figure 2.3.1B shows an 8 lead motor wired in parallel. Using this configuration the per phase inductance seen by 
the driver will be as specified.

Using the following equation we will show an example of sizing a motor for a MForce PowerDrive  used with an 
unregulated power supply with a minimum voltage (+V) of 18 VDC:

The recommended per phase winding inductance we can use is 3.6 mH.

Recommended IMS Motors 

IMS also carries a series of 23 and 34 frame enhanced stepping motors that are recommended for use with the MForce 
PowerDrive. These motors use a unique relationship between the rotor and stator to generate more torque per frame 
size while ensuring more precise positioning and increased accuracy.

The special design allows the motors to provide higher torque than standard stepping motors while maintaining a 
steadier torque and reducing torque drop-off.

Each frame size is available in 3 stack sizes, single or double shaft, with or without encoders. They handle currents up 
to 2.4 Amps in series or 6 Amps parallel, and holding torque ranges from 90 oz.-in. (M-2218-2.4) to 1303 oz.-in (M-
3447-6.3) (64 N-cm to 920 N-cm).

These CE  rated motors are ideal for applications where higher torque is required.

For more detailed information on these motors, please see the IMS Full Line catalog or the IMS web site at 
http://www.imshome.com. 

PHASE A

PHASE A

PHASE B

PHASE B

8 Lead Stepping Motor

Series Configuration

8 Lead Stepping Motor

Parallel Configuration

PHASE A

PHASE A

PHASE B

PHASE B

Specified Per Phase

Inductance

Specified Per Phase

Inductance

Actual Inductance

Seen By the Driver

Actual Inductance

Seen By the Driver

Maximum Motor Inductance (mH per Phase) =

.2 X Minimum Supply Voltage

NOTE: In 

calculating the 

maximum phase 

inductance, the 

minimum supply output 

voltage should be used when 

using an unregulated supply.