Carrier 69NT20-531-300 manual Evaporator FAN Motor Capacitors

the refrigeration unit into the container. The fan motor bearings are factory lubricated and do not require additional grease.

6.17.1Replacing The Evaporator Fan Assembly

WARNING

Always turn OFF the unit circuit breakers (CB-1 & CB-2) and disconnect main power supply before working on moving parts.

a. Remove upper access panel (see Figure 2-2) by removing mounting bolts and T.I.R. locking device. Reach inside of unit and remove the Ty-Rap securing the wire harness loop. Then unplug the connector by twisting to unlock and pulling to separate. NOTE: It may be easier to unplug the connector with the motor assembly partially pulled out (after step b).

6.18 EVAPORATOR FAN MOTOR CAPACITORS

The evaporator fan motors are of the permanent-split capacitor type. The motor is equipped with one capacitor used in the high speed circuit and another capacitor used for the low speed circuit.

6.18.1 When To Check For A Defective Capacitor

a.Fan motor will not change speed. For example: in the conventional perishable mode, the motors should run in high speed. In the economy perishable mode they should switch speeds and in the frozen mode, the mo- tors should run in low speed.

NOTE

The evaporator fan motors will always start in high speed.

b. Remove the four mounting bolts that secure the mo- tor-fan assembly to the unit.

c. Slide the fan assembly out from the unit and place it on a sturdy work surface.

d. Remove the motor and fan from the assembly. e. Replace the motor.

f. Lubricate the fan motor shaft with a graphite-oil solution (Never-Seez) and apply thread sealer (Loc- tite H, brown in color) to the two fan set screws. Install fan on the motor shaft, so that the coupling sur- face will be even with the end of the motor shaft.

g. Install the fan assembly in reverse order of removal. Apply power momentarily to check for proper fan rotation (refer to paragraph 2.3). If the fan spins back- wards, than motor wiring or motor is defective.

Replace access panel making sure that panel does not leak. Lock-wire the T.I.R. locking device(s).

4	3
5		2
6
		1
			8

9

7

1.	Bracket	6.	Cap Screw, Hxhd
2.	Flat washer, 3/8		5/16-18 x 1.25
3.	Bolt, 3/8-16 x 1.00	7.	Fan
4.	Locknut, 5/16-18	8.	Shim
5.	Flat washer, 5/16	9.	Evaporator Motor
	Figure 6-16. Evaporator Fan Assembly
T-309			6-12

b.Motor running in wrong direction (after checking for correct wiring application).

c.Motor will not start, and IP-EM’s are not open.

6.18.2 Removing The Capacitor

WARNING

Make sure power to the unit is OFF and power plug disconnected before removing capacitor(s).

The capacitors are located on the motor and above the evaporator fan deck they may be removed by two methods:

1If container is empty, open upper rear panel of the unit. The capacitor may be serviced after disconnect- ing power plug.

2If container is full, turn the unit power OFF and dis- connect power plug. Remove the evaporator fan motor access panel. (See see Figure 2-1). For removal of the evaporator fan assembly, refer to sec- tion 6.17.

WARNING

With power OFF discharge the capacitor be- fore disconnecting the circuit wiring.

6.18.3 Checking The Capacitor

If the capacitor is suspected of malfunction, you may choose to simply replace it. Direct replacement requires a capacitor of the same value. Two methods for checking capacitor function are:

1. Volt-ohmmeter set on RX 10,000 ohms.

Connect ohmmeter leads across the capacitor terminals and observe the meter needle. If the capacitor is good, the needle will make a rapid swing toward zero resistance and then gradually swing back toward a very high resistance reading.

If the capacitor has failed open, the ohmmeter needle will not move when the meter probes touch the terminals. If the capacitor is shorted, the needle will swing to zero resistance position and stay there.

2. Capacitor analyzer:

The function of the analyzer is to read the microfarad value of a capacitor and to detect insulation breakdown