SPX Cooling Technologies Hexacool Air Cooled Condenser none User Manual - Installation

9

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  without  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

six  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

nameplate  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 operation. If furnished with a mechanical O.L. set this 

at 110% over motor nameplate amps.

•  Motor rotation must be the same in both VFD mode and By-pass

mode.

•  If cable distance between the VFD and motor is greater than 31m a

DV/DT output filter is recommended to avoid damage to the motor.

31m distance is based on our field experience, the VFD manufacture

may state different distances and distance does vary depending 

on the VFD manufacture.

•  Program the VFD for variable torque output. Flux vector and con-

stant 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 en-

ergy 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 

Installation

Note