Motor Is Hot And Runs Intermittently; Electrical Short - Graco A Series Instructions-Parts List Manual

MOTOR IS HOT & RUNS INTERMITTENTLY
TYPE OF PROBLEM

ELECTRICAL SHORT

TYPE OF PROBLEM
Building circuit breaker opens
as soon as sprayer switch is
turned on.
CAUTION
Any short in any part of the
motor power circuit, which is
connected to the output side
of the bridge, will cause the
bridge to burn out immedi-
ately. Correctly diagnose and
repair all shorts before check-
ing and replacing bridge.
Building circuit breaker
opens as soon as sprayer is
plugged into outlet and
sprayer is NOT turned on.
Sprayer circuit breaker opens
after sprayer operates for only
5 to 10 minutes.
WHAT TO CHECK
If check is OK, go to the next check.
1. Check to see if sprayer has been operating
at high pressure with small tips, which
causes low motor RPM and results in exces-
sive heat build up.
2. Be sure ambient temperature where sprayer
is located is no more than 90 F and sprayer
is not located in direct sun.
3. Check to see if sprayer has been left in a
stalled condition (sprayer turned on, pres-
surized, but not operating) for long periods of
time.
WHAT TO CHECK
If check is OK, go to the next check.
1. Check all electrical wiring for damaged insula-
tion, and all terminals for loose fit or damage.
Also check wires between pressure control
and motor which are encased in conduit (21).
See page 34.
2. Check for missing inspection plate gasket (see
page 25), bent terminal forks or other metal to
metal contact points which could cause a
short.
3. Check motor armature for shorts by using an
armature tester (growler) or perform spin test.
See page 22. Inspect windings for burns.
4. Check bridge (308) by substituting with a good
bridge or by performing bridge test. See page
23.
CAUTION:Do not perform this check until arma-
ture is determined to be good. A bad armature will
immediately burn out a good bridge.
1. Check 'Basic Electrical Problems' on page 16.
2. Check ON/OFF switch (302) See page 26. Be
sure the sprayer is unplugged!
wires from switch. Check switch with ohmme-
ter. The reading should be infinity with the ON/
OFF switch OFF, and zero with the switch ON.
CAUTION: A short in the motor circuit will burn the
bridge out immediately, which in turn usually
causes the ON/OFF switch to fail in the closed
mode.
1. Check electrical supply with volt meter. Meter
should read 105 to 125 VAC.
2. Check tightness of pump packing nut. Over-
tightening nut tightens packings on rod, re-
stricts pump action, and damages packings.
3. Check pressure control adjustment. See
page 30. Turn off and unplug sprayer.
4. After determining that there is no short in sys-
tem, reset circuit breaker button.
WHAT TO DO
If check is not OK, refer to this column.
1. Decrease pressure setting or increase
tip size.
2. Move sprayer to shaded, cooler area if
possible.
3 Turn of f sprayer whenever you stop
spraying for a while and relieve
pressure.
WHAT TO DO
If check is not OK, refer to this column.
1. Repair or replace any damaged wir-
ing or terminals. Securely reconnect
all wires.
2. Correct faulty conditions.
3. Replace motor. See page 34.
4. Replace bridge. See page 28.
Disconnect
2. Replace ON/OFF switch. See page
26.
1. If voltage is too high, do not operate
sprayer until corrected.
2. Loosen packing nut. Check for leaking
around throat. Replace pump pack-
ings, if necessary. See page 36.
3. Adjust pressure control. See page 30.
4. If circuit breaker continues to open (but-
ton pops up), replace the circuit
breaker. See page 27.
fluid
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