Altitude adjustment – Rockwell Automation 1502 Medium Voltage 400A Contactor - Series E User Manual
Page 53
Rockwell Automation Publication 1502-UM052H-EN-P - June 2013
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Maintenance
Chapter 4
4. With the contactor still clamped, depress the latch lever and release
allowing it to spring up. Ensure smooth, unimpeded motion.
5. Remove the clamp and allow the armature to move out against the roller
such that the contactor is in the “latched” condition.
6. Using the manual trip lever, trip (drop out) the contactor. Apply 2 to 3 lb.
of force to trip the contactor. If too little force is required, the mechanism
must be moved away from the armature slightly (toward the front of the
contactor). If too great a force is required, the mechanism must be moved
toward the armature slightly (toward the back of the contactor). If
adjustment is required, the contactor must be clamped closed and the set-
up procedure repeated with thicker or thinner feeler gauges as required.
Altitude Adjustment
Altitude will affect the performance of a vacuum contactor. Atmospheric pressure
assists in closing the main contacts by exerting force on the bellows at the
movable end of the vacuum bottles. The force is proportional to the difference
between the internal bottle pressure and external atmospheric pressure and
adjustments to the operating mechanism must be made to balance the change in
closing force. The 400A contactors are equipped with return springs appropriate
for the specific altitude they will be operating at.
Note: IntelliVAC vacuum contactors typically use the bronze-colored return
springs, and the IntelliVAC and IntelliVAC Plus control modules are used to
compensate. If a mechanical latch contactor is applied without IntelliVAC or
IntelliVAC Plus control, the springs must be changed. (Electrically held
contactors (Series E or later) may only be used with IntelliVAC control. Refer to
publicatio
If a relay controlled latch contactor is to be moved to a different altitude, refer to
to determine the correct return springs for the new altitude range. Simply
replace the springs and correct the rating label information (catalog number,
altitude range and current rating) per
. Note the change Basic Impulse
Rating (B.I.L) as it relates to altitude.
ATTENTION: The return springs exert a significant force on the armature plate.
To avoid injury, do not place fingers between the armature plate and the stop
bracket at any time.
IMPORTANT
This is a sensitive and critical set-up. A few thousandths of an inch makes a
noticeable difference in the function of the latch. A mechanism which trips too
easily may result in nuisance tripping. A mechanism which requires too much
force may result in failure of the coil to trip the latch.
IMPORTANT
Do not change springs on contactors whose catalog number end in ‘-0’.