Manitowoc Ice QF0800 Section, Electrical System, 6-49, MOTOR SPEED SENSOR Function, Failure Modes

Section 6 Electrical System

MOTOR SPEED SENSOR

Function

The motor speed sensor verifies that the gearbox motor is rotating at the correct speed.

Failure Modes

MOTOR SPEED SENSOR OPEN OR DISCONNECTED (ICE MACHINE WILL NOT START.)

Performs initial start-up procedure. Ten to 15 seconds after the ice machine enters Water Flush (1), the ice machine will initiate an Automatic Shut-Off cycle, flash the Speed light and remain off for 60 minutes. (Refer to “Gear Motor Speed” for additional information.)

MOTOR SPEED SENSOR CLOSED OR SHORTED (ICE MACHINE WILL NOT START.)

Performs initial start-up procedure. Ten to 15 seconds after the ice machine enters Water Flush (1), the ice machine will initiate an Automatic Shut-Off cycle, flash the Speed light and remain off for 60 minutes. (Refer to “Gear Motor Speed” for additional information.)

Check Procedure

1.Allow time for the evaporator to warm. Disconnecting power in the Freeze cycle will result in ice build-up between the evaporator and auger.

2.Verify the motor speed sensor is in place and securely attached to the motor.

3.Verify the gearmotor run capacitor is functional.

4.Place toggle switch in the OFF position and place an identifying mark on the evaporator/gearbox coupling. This will provide a reference point to verify the coupler is rotating.

Move the toggle switch to the ICE position and verify the motor shaft and coupling are turning, then observe the Speed light.

(If the gear motor and coupling will not rotate, the switch is operating correctly.)

Speed light is:	Cause
On	This is normal operation.
after 3 to 5 seconds
Off	Replace motor
	speed sensor.
On after 3 to 5 seconds
and control board	Replace control board.
terminates Freeze cycle

To verify coupling/auger RPM (revolutions per minute):

1.Verify line voltage is within 10% of ice machine nameplate rating when low RPM is suspected.

2.Verify the gear motor run capacitor is functional.

3.Place identifying mark on coupling.

4.Count coupling revolutions for 2 minutes.

5.Divide coupling revolutions by 2 (example: 31 coupling revolutions ÷ 2 = 15-1/2 RPM).

Minimum revolutions per minute:

QF400 = 9 RPM

QC700 = 15 RPM

QF800 = 15 RPM

QF2200/QF2300 = 11.6 RPM

Speed Sensor

QF400

SV2046

Part No. 80-1214-3 Revised 8/2003 6-49