Application note AN-ODE-2-045
AN-ODE-2-045 Using Multiple Motors In Parallel
Optidrive Applications Support Library
Using Multiple Motors In Parallel
1 – Fundamental - No previous experience necessary
2 – Basic – Some Basic drives knowledge recommended
3 – Advanced – Some Basic drives knowledge required
4 – Expert – Good experience in topic of subject matter recommended
Overview
In some applications it is possible to operate multiple motors connected to a single Optidrive E2. This application note described
the considerations and guidelines that should be given to such applications in order to select the correct drive and to operate it
successfully.
Multiple Motor Applications
Multiple motor with single drive operation is generally suited to applications where the motors are always required to run at
approximately the same speed and where motor loads are not mechanically coupled together.
Drives can be used to run multiple motors in applications where slight motor speed variation (generally only a few percent) does
not cause a problem in the overall process being performed (motors speeds are not required to be precisely synchronised). Ideal
applications include fans and pumps, where accurate speed synchronisation within the application is generally not required.
General Rules for Multiple Motor Applications
Providing that all the motors are permanently connected to the Optidrive E2, the required drive can usually be selected
based on the total of the motor current ratings connected.
The total cable length required should not exceed the maximum allowed for the drive in use – refer to the User Guide
for details of the maximum cable length. The allowed total cable length can be increased by 100% if an output filter is
used.
To avoid possible motor damage, each individual motor must be protected by a thermal overload device. The drive
over-current protection settings cannot be used to protect multiple motors.
Only standard AC industrial three phase motors should be used.
The Effective Switching Frequency Parameter (P-17) should be set to the minimum value (normally 4kHz).
The Spin Start function (P-33) cannot be used
Providing the above design rules are met and the motors are permanently connected to the drive, the drive should be sized
based on the total nameplate current (not kW or HP) of the connected motors.
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