Autoquip FREIGHTLIFT FL4M - Manual (Page 83)

83
2. The motor turns the gears in the reducer, which in turn rotates the drive shaft. The
sprockets on the shaft also turn resulting in the raising or lowering of the lifting
chains (because the motor starter is reversible, the direction of travel can be
alternated). The lifting chains are fastened to the wheel blocks, which are in turn
bolted to the carriage, thereby raising or lowering the carriage.
3. When the carriage arrives at the landing it has been called to, the level limit switch
(one per level) is activated by the striking of a mechanical cam attached to the side
of the carriage. When activated, this switch cuts the power to the motor circuit, the
motor starter contacts drop out (open), the motor stops, and the motor brake is
automatically applied thereby stopping and holding the carriage at that landing.
4. The over-travel limit switch is a safety device mounted directly above the uppermost
level limit switch. The only time it should activate is if there is a failure of the
uppermost level limit switch. Again, the over-travel switch is activated by the
striking of a mechanical cam attached to the side of the carriage. When activated, it
cuts the power to the motor circuit.
NOTE: Always find out why the over-travel switch is activated and be sure to
correct the problem before making the lift operational again.
5. The lift is supplied with an Electrical Current Sensor (ECS) with Trip Relay, so that
excessive current draw due to carriage overloading or jammed carriage condition
will cause the ECS to quickly cut off electrical power to the gear motor and prevent
structural damage to the lift.
NOTE: Only a qualified technician should be allowed to reset the ECS to regain
power to the lift gear motor.
NOTE: Always find out why the ECS cuts off power to the motor and be sure to
correct the problem (load jam, over-load, etc.) before making the lift operational
again.
6. If any of the lifting chains or drive chains should go slack or break during operation,
the corresponding slack chain sensor will activate and cut off the electrical power to
the motor and automatically apply the motor brake.
NOTE: Always find out why the slack chain sensors are activated, be sure they are
set according to the procedures set forth herein, and be sure to correct the problem
(carriage interference, etc.) before making the lift operational again.
NOTE: The locking cams mounted to the carriage will be engaged only if the chain
breaks.
CAUTION!
Do not run operate the lift until all limit switches and sensing switches
have been confirmed to be installed & adjusted correctly! Failure to do so
could result in personal injury and/or permanent equipment damage.
OPERATING INSTRUCTIONS