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When using a two-speed starter:
• Motor rotation must be the same at slow speed and high speed.
• Single winding motor requires a starter with a shorting contactor.
• Two-winding motor requires a starter with out a shorting contactor.
• All two-speed starters must have a 20 second time delay relay when
switching from high speed to low speed.
Do not start the motor more than four to five times per hour (each
low speed start and each high speed start count as one start).
When using a VFD:
Before beginning, ensure that the motor is rated for “Inverter Duty”
per NEMA MG-1, part 31.
• Set the VFD solid state overload protection to 119% of motor name
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plate amps and set “maximum current parameter” in the VFD to motor
nameplate amps. “Maximum current parameter” will reduce fan speed
and limit amp draw to nameplate amps during cold weather opera-
tion. If furnished with a mechanical OL set this at 110% over motor
nameplate amps.
• Motor rotation must be the same in both VFD mode and bypass mode.
• If cable distance between the VFD and motor is greater than 30m a
DV/DT output filter is recommended to avoid damage to the motor. 100
feet distance is based on our field experience, the VFD manufacture
may state different distances and distance does vary depending on
the VFD manufacturer.
• Program the VFD for variable torque output. Flux vector and constant
torque modes may damage the gearbox.
• Do not start and stop the motor using the safety switch at the motor.
If the drive is being commanded to run and the load side is cycled ON
and OFF with the safety switch this may damage the VFD.
Using a VFD in cooling applications has advantages over traditional single
or two speed motor control. A VFD can reduce the cost of electrical energy
being used and provide better temperature control. In addition, it reduces the
mechanical and electrical stress on the motor and mechanical equipment.
Electrical savings can be large during periods of low ambient temperature
when the cooling requirement can be satisfied at reduced speeds. To benefit
from these advantages, it is important that the drive be installed correctly.
Marley VFD and controls are specifically designed for our cooling products. If
you have purchased a Marley VFD and/or controls package, please follow the
instructions in the User Manual for that system. Most VFD problems can be
installation
Note
Note
