Instruction Bulletin
Instructions for Installation,
Page 3
Effective: July 2016
Operation and Maintenance of the
SL800 Classic 7.2 Kilovolt, 720 Amp. Vacuum Contactor
For more information visit:
www.eaton.com
IB48082
INSTALLATION
ALL WORK PERFORMED ON THIS CONTACTOR
SHOULD BE DONE WITH THE MAIN
DISCONNECT DEVICE OPEN AND LOCKED OUT.
AS WITH ANY CONTACTOR OF THIS VOLTAGE,
THERE IS DANGER OF ELECTROCUTION
AND/OR SEVERE BURNS.
MAKE CERTAIN THAT POWER IS OFF. CHECK
FOR VOLTAGE WITH VOLTAGE SENSOR OR A
METER OF THE APPROPRIATE RANGE.
MAKE CERTAIN THAT ALL TRANSFORMERS
ARE ISOLATED TO PREVENT FEEDBACK AND
THE RESULTANT GENERATION OF HIGH
VOLTAGE.
The
SL800 Classic
contactor is a direct replacement
for SJA800A contactors in Classic Ampgard starter
assemblies. No mechanical changes to the starter
cell or the contactor are required when installing the
SL800 Classic contactor.
The contactor weighs about 210 pounds. It should
be handled gently to avoid damage to the vacuum
bottles and factory adjustments. A horizontal plate is
provided at the front for pulling the contactor out of
its cell, or for pushing it back into place.
When a type SJA contactor is installed in a medium
voltage controller it can be moved to a draw out
position or removed from the enclosure as follows:
1. Provide a lift truck or suitable platform to receive
the contactor as it comes out.
2. Make sure all circuits are de-energized.
3. Remove the three power circuit fuse assemblies
using the fuse puller supplied with the starter.
4. Disconnect the control plug and stow it so that the
cable will not be damaged. Disconnect the two 3-
point separable terminal blocks on the right front of
the isolating switch.
5. Trip the latch on the left side by holding it upward
(using your foot if desired, when unit is at floor
level).
6. While holding the latch up, pull the contactor out
ward. It will roll forward and should re-latch at a
detent position, partially out of the cell. All routine
inspection and maintenance can be done with the
contactor in this latched position.
7. To remove the contactor completely, reverse the
latch, pressing it downward. The contactor can then
be rolled out of its cell.
Once the contactor is on the floor, it can be moved
easily by means of a short length of 0.75-inch (19.1-
mm) pipe inserted into a bracket on the top front of
the right side sheet. The contactor can be pushed or
pulled like a wagon in this manner.
To install the SL800 Classic contactor, reverse the
procedure.
Fig. 1 Moving the Contactor
CONTACTOR OPERATION
The SL contactor has its main contacts sealed inside
ceramic tubes from which all air has been evacuated,
i.e., the contacts are in vacuum. The arc simply
stops when the current goes through zero as it
alternates at line frequency. The arc usually does
not survive beyond the first half cycle after the
contacts begin to separate. The ceramic tube with
the moving and stationary contacts enclosed is called
a vacuum interrupter or a vacuum bottle and there is
one such bottle for each pole of the contactor. A
metal bellows (like a small, circular accordion) allows
the moving contact to be closed and pulled open
from the outside without letting air into the vacuum
chamber of the bottle.
