Crane and Hoist duty motors from Bharat Bijlee are ideal for frequent starts/stops and reversing. They are also used for applications such as material handling, weirs and sluices, lifts of all types and auxiliary motors in rolling-mills or wherever intermittent drives are required. They conform to IS : 325 for Three-phase Induction Motors and IS : 4722 for Rotating Electrical Machines. Intermittent periodic duty This includes a period of operation at constant load and a de-energised period, which are too short to attain thermal equilibrium during one cycle. The starting current does not significantly affect the temperature rise for this type of duty. Intermittent duty with starting

This includes a period of starting, a period of operation at constant load and a de-energised period, which are too short to attain thermal equilibrium during one cycle. The starting affects temperature rise, as load GD2 is higher than rotor GD2 and/or no. of starts/hour is high, for this type of duty. The motor is stopped after switching off, either by natural deceleration, or by a mechanical brake, without additional heating of the windings.

Intermittent duty with electrical braking
The common Cyclic Duration Factors (CDF) for the above duties are 25%, 40% and 60%. Tables given herein are for load GD2 equal to or less than rotor GD2. For cases where load GD2>rotor GD2 the motor should be selected from the table with a higher no. of starts/hr. as per the formula No. of starts allowed = No. of starts as per table x 2 x GD2 of rotor / (GD2 of rotor - GD2 of load).

Rotor type and identification of motors The motors are identified by the type reference.
a) MC for squirrel cage rotors and
b) MP for Slip Ring (Wound) rotors.

Squirrel cage rotors are of die cast Aluminium material for low starting currents with high starting torques, suitable for the large number of starts/stops required.

Enclosure
Totally enclosed fan cooled (TEFC) with degree of protection IP55 as per IS : 4691. IP56 or IP66 on request.

Voltage, frequency and ambient temperature
Three phase 415 Volts 50 Hz supply with ± 10% Voltage & ± 5%, frequency variation, and 450C ambient temperature.

Type of mounting and dimensions
Foot, flange or face mounting, and combination, are Offered.

Insulation
a) For squirrel cage type MC class F for stator

b) For slipring type MP class F for stator and rotor. Temperature rise for stator windings are limited to class B limits.

Invertor Applications
All crane duty motors are suitable for Invertor Duty applications. Motors for Invertors can be supplied upto 315M frame size

Ratings:
4 poles:- 2.2KW – 15KW (Frame 100L – Frame 160L)

6 poles:- 1.1KW – 10KW (Frame 100L – Frame 160L)