Metso MP1000, Technical Reference Manual

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SECTION 2 - GENERAL INSTALLATION INFORMATION
MP SERIES CONE CRUSHER TECHNICAL REFERENCE MANUAL
2-21
2.9 V-belt Precautions
Some of the do’s and don’ts in connection with
proper V-belt drive operation are as follows:
1. DO - Check belt tension frequently during
the first few days of run-in operation. When
the belts have had time to become seated in
the sheave groove, retension the belts. New
belts have a certain amount of initial stretch
and will require additional tensioning.
2. DON’T - Overtighten belts as too much
tension shortens both belt and bearing life.
Maintain uniform tension. Idle belts should
appear snug or tight; in motion, they have a
slight sag on the slack side.
3. DO - Keep drives well ventilated as heat
build-up over 60°C (140°F) causes belt life
to become shortened. The sides of the belt
guard must be designed to allow for
adequate circulation of air. Either perforated
plate or expanded metal is ideal for this type
of application.
4. DON’T - Allow any oil or grease to come in
contact with the belts as excessive oil causes
the rubber to swell and the belts to fail
prematurely.
5. DO - Make V-belt drive general inspections
on a periodic basis. The following points
should be checked at each inspection.
a. Loss of crusher speed - check tension.
b. Unequal stretch - check for internal
breaks.
c. Excessive elongation - check for
overload.
d. Belt softening or swelling - check for oil
or grease.
e. Belt hardening and cracking - check for
excessive heat.
6. Values from Table 2-6 and Table 2-7 are
based on V-belts that are of typical
construction. If V-belts of other construction
are used the tension obtained from using
these values may result in too high of a
tension and could result in bushing or motor
bearing failure.
7. Monitor the temperature of the countershaft
box after tensioning belts to avoid possible
bearing problems resulting from over
tensioning. Reduce belt tension if
countershaft box exterior temperature
increases and exceeds oil drain line
temperature by 3°C (5°F) or more.
8. After any belt tensioning adjustment, the
countershaft coast down time should be
rechecked. A significant decrease from
previous readings may indicate that the belts
have been overtensioned.
NOTICE
Monitor countershaft bushing RTD and
reduce belt tension if temperature increases
and exceeds oil drain line temperature by
6°C (10°F) or more.