SPX Cooling Technologies Marley MD Humidifier User Manual


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9
Installation
Motor Wiring
Wire motor leads as shown on the motor nameplate matching the supply
voltage. Do not deviate from the motor nameplate wiring.
Either of following symbols may be shown on the motor nameplate –
Δ, Δ Δ
, Y, or YY. These symbols represent how the motor is constructed on
the inside and in no way have anything to do with a Delta or Wye electrical
distribution system serving the motor.
When using a starter:
• Setmotoroverloadprotectionto110%ofmotornameplateamps.
This setting allows the fan motor to operate during cooler weather.
During cooler weather it is common for the motor to draw 6 to
10%higherthannameplateamps.Highampsarecommonduring
tower commissioning when the tower is dry and the ambient air
temperature is cool.
• Donotstartthemotormorethansix times per hour. Short cycling
the tower will cause fuses, breakers or O.L.s to operate and will
decrease motor life.
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contac-
tor.
• 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.
Note
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