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17
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Recommended magnetic contactors
Model
Magnetic
contactor
ST-0.2D Type, ST-0.4D Type
SP-0.2D Type, SP-0.4D Type
ST-0.4D-U Type
MS-2 x N20
(min)
ST-0.75D Type
ST-0.75D-U Type
MS-2 x N35
(min)
ST-2.2D Type
MS-2 x N50
(mm)
Notes :
1.
The thermal relay should be
removed from the magnetic
contactor.
2. Magnetic contactor listed
above is applicable only
when the motor is operated
under the rated condition.
6. TEST OPERATION
(1) Before starting operation, measure insulation resistor of the entire magnetic contactor (remote
control switch station) secondary circuit including trolley line, using a 500V megger. Insulation
resistance should be larger than 0.4Megohm.
(2) Check that the runway rails have been grounded properly (less than 100
Ω
).
(3) No- load operation
Close the power contactor and jog UP button under no -load condition to check if the hook block
goes up. If the hook block goes down, change power phase sequence as follows:
Open power contactor and interchange connection on the contactor secondary side between
R phase and T phase.
Note : Connection should not be changed on the remote control switch station
(otherwise, “over- winding prevention limit switch” becomes inoperative).
Perform the same check and change the power phase sequence, if necessary, for bridging and
traverse motors.
Next, check lifting
I
lowering operation (check the over - winding prevention limit switch), bridging
and traverse operation ····· the operation should be smooth and quiet.
(4) Hang a weight (rated load) from the hook block and perform test operation (bridging and
traverse )to check crane motion, rails and collector function.
During test operation, allow the crane saddle to strike the end stoppers. If two rubber cushions
do not strike the end stoppers at the same time, change location of one rubber cushion so that two
cushions strike at the same time.
