MDE-4334C Atlas Start-up and Service Manual · April 2008
Page 7-63
Pump Motor
Hydraulic/Mechanical Components
Pump Motor
About Electric Motor for Self-contained Pump Units
Motor Loads
The following chart shows the maximum running amperage that can be expected for the pump
motor, unless noted otherwise:
Model
Motor Rating
115 V
50/60 Hz
1PH
230V 50/60 Hz 1PH
230V 50/60 Hz
3PH
380V 50/60 Hz
3PH
8X5XK, 9X52K, 9X53K
13 amps
6.5 amps
3.4 amps
2.3 amps
9X40K
13.0 amps
per motor
6.5 amps per motor
3/4 amps per motor
2.3 amps per motor
9850K
13.0 amps
6.5 amps
3.4 amps
2.3 amps
Thermal Overload
Most motors have a thermal overload switch to open the circuit automatically if the motor is
overheated or drawing excessive current. When the switch cools, it activates and turns the
motor back on. Motors do not require a manual reset. The 220/380 VAC motors do not have a
thermal overload switch.
If overload shut-off occurs frequently:
• Check the voltage switch for proper voltage selection (110/230/240/380).
• Check for free pump and motor shaft rotation.
• Check the Pump Bypass Valve and relief pressure setting.
• Check the belt tension.
• Check the line voltage during operation with the nozzle closed, and then with the nozzle
open. Low or high voltages (greater than +/- 10%) can cause overheating or premature
failure.
• NFPA requires explosion-proof motors. Only use an Atlas-specified explosion-proof
motor for replacement.
Service Tips
• Frequently, low voltages during operation can result when the PRV is set to too high a
pressure, or wiring to the motor is inadequately sized for the motor load.
• Premature motor failures are usually caused by continuous operation at too low a voltage
or high pressure setting at the PRV.