MOTOR : The motor is three phase squirrel cage, conical rotor type working on 440 volts, 3P,50 Hz A.C. supply. This motor is specially designed for hoist and crane and is insulated by class 'F' type of insulation according to B.S : 2613. The starting and stalling torques of this motor are 220 % and 290 % of the full load torque. The motor is rated at 40 % CDF.
BRAKE : The axial movement of the rotor is one of the characteristics of the conical rotor type of motor. This characteristic is taken advantage of in the actuation of the brake. When the motor is started the rotor is axially pulled into the magnetic centre of the stator and the brake is released. As soon as the current is cut off the brake spring presses the brake disc against the cover and the brake is applied. The braking torque is 100 % above the motor torque at the rated load.
The maintenance and adjustment of the brake is very simple and can be done without removing any part. The brake disc and brake end cover are both made of high grade cast iron and the brake lining is of 'Ferrodo' type.
GEAR BOX : The gear box is made of high grade cast iron. The precision spur gears are machined from alloy steel and are fitted with ball / needle roller bearings. The gear box is filled with grease.
ROPE DRUM : The rope drum is rolled welded and precision machined. This rope drum is supported on large diameter roller bearings on both ends and the drive is through internal gears.
This rope guide moves on the drum like a nut and prevents the rope from overriding and loosening.
ROPE : Generally 6 x 37 / 6 x 36 construction fibre core preformed type, ungalvanised wire rope is supplied. (Galvanised and steel core wire ropes can also be supplied, if specifically asked for).
MAIN HOUSING : All hoist parts are enclosed in the main housing thus forming a better looking integral unit. The main housing like the rope drum is also of rolled and welded construction, equipped with mounting bracket.
LIMIT SWITCHES : Every hoist is provided with built in limit switches to control the top and bottom positions of the hook. Tappets can be adjusted on limit switch rod to any position in between the range provided. These limit switches are actuated by the rope guide.
CONTROL : The hoist is controlled by a pendant push button station. Supply to the pendant push button station i I s of 110 volts as per IS specifications.
MICROSPEED : All hoists can be fitted with a micro speed attachment which reduces the hoisting speed to 1/10th of the main hoisting speed. The micro speed attachment works independent of the load and main hoist. There is a separate control for the micro speed. This arrangement is invaluable in the handling of bulky, heavy and delicate loads.
TESTING : Every hoist unit is tested at 125 % of the rated load capacity on single fall of rope. Even the components pass through rigorous inspection tests before the hoist is approved for dispatch.
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