TM 5-3895-374-24-1
Recommendations for use
of the motor/speed controller combination
Association with
ALTIVAR speed controllers are designed to drive motors with a corresponding power rating
different motors
They can, however, be used with motors having different power ratings providing that
certain precautions are observed
Depending on the motor characteristics, and the performance necessary for the application,
the use of a special software is recommended See part 2 of this document, "Special
Applications" (p 81)
Motor power < speed controller rated power
This combination is possible
As compensation is not at the optimum level, this can lead to a reduction in continuous
torque at low speed Adjust the U/f ratio if necessary (p 48)
If motor power is < 0,5 controller rated power, correct adjustment of motor thermal
protection is impossible (p 49)
Cancel the internal protection and use standard external protection (overload relay or
thermistors)
Motor power > rated power of the controller
Magnetizing current peaks limit this combination to the motor power immediately above the
controller rating
Again, compensation is not at the optimum level, and the U/f ratio should be adjusted if
necessary (see p 48) The motor current must remain lower than, or equal to the speed
controller’s rated current Fit a three phase inductance between the speed controller and the
motor, if necessary (p 36)
Motors in parallel
Speed controller selection
Speed controller in > In1 + In2 + ...Inx
Each motor should be protected by a thermal
overload relay
Compensation is not at the optimum level Adjust the U/f ratio if necessary (p 48) If the
motors have different power ratings, the ratio adjustment can only be a compromise If the
load is to be shared between the motors, override the slip compensation (p 45)
If there are 2 3 motors, fitting a three phase inductance between the speed controller and
the motor is recommended (p 36)
(page 3-183)
