MC3 ChipMaster, Operation & Maintenance Manual, Page: 37 / 63

2
(B) For the 500A and 700A models:
Maximum Rated Torque
With the 3 cap screws backed out until the points are
below the surface of the nut, run the nut up finger tight
or slightly less than finger tight, and alternately tighten
the cap screws no more than
1
/
2
turn at a time until
their heads bottom. Do not overtighten the cap screws
nor completely flatten the disk spring. This should give
the maximum rated torque, but since there are several
variables that affect the setting, it should be checked per
step 5 and readjusted if necessary.
Less Than Maximum Rated Torque
With the 3 cap screws backed out until the points are
below the surface of the nut, run the nut up finger tight;
then back off an appropriate amount. Alternately tighten
the cap screws no more than
1
/
2
turn at a time until their
heads bottom. Check setting per Item 5. Do not over-
tighten the cap screws nor completely flatten the disk
spring.
5. Torque Checking
To check the Torque Limiter for the required slip torque,
mount the Torque Limiter on a stub shaft and fasten in a
bench vise. Wrap the center member (if a sprocket) with a
chain and load the chain with weights until the center
member rotates. If the center member is a plate, attach a
chain or cable to the center member. The breakaway torque
will be equal to the radius of the center member in feet times
the weight in lbs. on the chain. The breakaway torque should
be slightly higher (5% to 10%) than the required slip torque.
If the slip torque is too high or too low, readjust torque limiter
as in step 4-tightening or loosening the adjusting nut as
required. On the 500A and 700A sizes, back off the cap
screws until the spring force is relieved before tightening or
loosening adjusting nut. After readjustment, check the
breakaway torque in the manner outlined above.
After final adjustment, lock the adjusting nut by bending
lock-washer tab over nut (models 250A and 350A). On
models 500A and 700A, the 3 cap screws have cup ends
which lock into the pilot plate.
6. THIS ADDITIONAL STEP IS APPLICABLE TO THE
TORQUE LIMITER COUPLING ONLY:
(a) Never use a torque limiter alone as a coupling.
When shaft coupling is required in conjuction with slip
protection, use a torque limiter coupling.
(b) After setting torque limiter per steps 4 and 5 above
(with flat sprocket installed as the center member in
torque limiter), mount it on the shaft. Then mount the
coupling half (the sprocket with the hub) onto the shaft
to be coupled, leaving a gap between adjacent sprocket
faces.
(d) When the shafts are properly aligned, wrap the coupling
chain around the sprocket teeth and connect the chain
ends by inserting the pin which is furnished loose with
the coupling. The chain will wrap and connect easily on
properly aligned sprockets.
7. Caution
The operating characteristics and capacity of Torque Limiters
are affected by atmospheric conditions, moisture, lubricants,
and surface corrosion. To illustrate, the life of the friction
facings may be greatly reduced by rust on the center plate.
The Torque Limiter ratings are based on average conditions.
For best results, the Torque Limiter should be adjusted under
conditions similar to those in which it will be used.
8. Maintenance
At periodic intervals, or if proper torque is not being main-
tained, inspect Torque Limiter for presence of oil, grease,
moisture, or corrosion on the driving surfaces and for proper
setting of spring load. Clean and adjust as required. Friction
facings and bushings are the only parts that should normally
require replacement.
(c) Align the shafts as accurately as possible to obtain
the maximum service life from the coupling.
Maximum Angular Misalignment -
½
°
For Technical Support Call 1-800-626-2093.
Torque Limiter Size 250A 350A 500A 700A
Gap Width-Inches 5/16 13/32 15/32 5/8
Torque Limiter Size 250A 350A 500A 700A
Maximum Parallel
Misalignment-Inches
.010 .012 .015 .020
Morse is a registered trademark of Borg-Warner Corporation, used herein under exclusive license.
Emerson and Emerson Industrial Automation are trademarks of Emerson Electric Co. or one of its
affiliated companies.
©1998, 2001, 2009 Emerson Power Transmission Corps., All Rights Reserved.
MCIM09026 • Form 4446-004 • Printed in U.S.