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MODEL 365A & E365A VIBRASWITCHES
Section 5 - MAINTENANCE
5.1 TROUBLE SHOOTING
Vibraswitches do not normally require any repair;
however, listed below are some of the possible
malfunctions that may occur and their recommended
solutions.
Whenever tightening cover bolts tighten to 75 – 105
inch lbs (8.5 – 11.9 Nm).
a. Functional Test (Ref. Figure 4-1)
This test may be performed with the Vibraswitch in
its housing or removed from its housing. Therefore,
it is not necessary to remove the housing from the
machine.
1. Place the Vibraswitch on a table with the
mounting surface or terminal blocks down on the
table (setpoint adjusting screw and reset button
facing up).
2. Press the reset button. If switch does not reset
(armature latched on stop pin), turn setpoint
adjustment screw CCW until switch can be
manually reset.
3. Slowly turn setpoint adjusting screw CW until
switch trips. This is the zero trip point which is the
amount of spring tension required to overcome the
1 g force exerted by the earth's gravitational pull.
4. Note set point setting.
equals approximately 1 g. Setpoint scale is marked
in 0.1 g increments.
screw one complete turn CCW.
setting above the earth's gravitational pull.
5. Manually reset the switch (press reset button).
6. With the reset button to your left and the
Setpoint adjustment screw to your right, slowly
rotate the Vibraswitch toward you 90°. The switch
should trip when the mounting surface or terminal
block is in a vertical plane and the earth's
gravitational pull is not aiding the holddown (lower)
magnet to hold the armature against the stop pin.
If the Vibraswitch does not pass the above test
contact
the
nearest
representative for repair or replacement of the
Vibraswitch.
b. Vibraswitch Will Not Reset
1. Dirt and/or metal chips on magnet –
Clean magnets without removing or rotating them.
NOTE
One complete turn
Turn setpoint adjustment
This is a 1 g
Robertshaw
2. Reset Assembly Binding –
Check for interference from switch insulator.
3. Broken Leaf Spring (Ref. Figure 4-1) –
Not repairable in the field.
Robertshaw sales representative for repair or
replacement of the Vibraswitch.
4. Open Reset Coil –
Check for continuity and proper coil resistance as
specified in Table 5-1.
NOMINAL
VOLTAGE
24 VDC
48 VDC
117 VDC
120 VAC
240 VAC
If coil fails continuity/resistance check replace coil
or
contact
representative for repair or replacement of the
Vibraswitch.
c. Unable to adjust Setpoint Setting to Obtain
Tripping
Improper air gap between Holddown (lower)
Magnet and Armature –
Not repairable in the field.
Robertshaw
replacement of the Vibraswitch.
d. Switch does not actuate
Defective switch –
Verify by manually moving the Armature between the
latched (tripped) position and the armed (reset)
position and listen for an audible click of the switch.
Verify contact by performing a continuity check.
If the internal switch is to be replaced or adjusted in
the field make sure that the actuation point occurs at
mid travel of the armature (lever).
sales
- 12 -
Contact the nearest
Table 5-1
Reset Coil Resistance
RESISTANCE
(OHMS ± 10%)
55
230
850
Check for continuity. (Diode
prevents actual resistance reading)
the
nearest
Robertshaw
Contact the nearest
sales
representative
909GF294G
sales
for
repair
or
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