Brake Motors for Crane, Hoist & Other Applications:
'Delta' brake motors are offered for various applications requiring almost instantaneous stopping of the driven load.These motors are offered in frame sizes 71 to 160M.Their operation is of 'fail safe' type i.e.the brake is applied, when, power to the motor is switched off, if power failure occurs.

They conforms to IS : 325 - for three phase induction motors and IS : 4722 for rotating electrical machines.The size of motor is governed by the number of start/stops per hours.

Note:
Motors with other voltage & frequency and higher ambient temperatures (> 40 ⁰C) and suited for wider power supply variations can also be given.

Construction:
A Brake Motor is an integral combination of an A.C.induction motor and a disc type, fail safe, electromagnetic brake unit.These motors are either foot, flange or face Mounted or combination of any two. Dimensions are of squirrel cage types are as per IS:1231 (for foot mounting), IS:2223 (for flange mounting), IS: 2253 (For Face Mounting) and enclosure is either totally enclosed fan cooled (TEFC) or Totally enclosed surface cool (TESC) with degree of protection IP54, IP55 as per IS : 4691. It consists of the following:

• A.C. Sq. Cage Induction Motor.

   

• Encapsulated brake coil housed on the non-driving end Endshield.

   

• Brake liner mounted on the armature disc.

   

Operation:
Under no power condition Brake springs keep the Brake liner which is made out of cork material, pressed against stationery disc of the Brake. This brake liners are mounted on a disc engaged with a square block, mounted on the shaft, thereby prevents rotor shaft rotation.When power is switched on,the brake coil gets energized.It instantly attracts armature disc by overcoming the spring force. This action results in releasing of the brake allowing the rotor to rotate freely.
When power fails or when it is switched off , the Brake coil gets de-energised.This results in the spring pressing the brake liner against stationery disc of the brake resulting almost instantaneous braking of rotor. Fail safe condition is thus ensured.

Special Features:

• Being simple and rugged-in construction, these motors need very little maintenance. In the rare event of failure, repair is simple and easy.

   

• No separate supply is necessary for brake coil energisation, because the brake coils are working on A.C. and their supply leads are directly connected to the motor terminals.

   

• Special brake liner is used, Which ensures that, the braking torque Value remains quite stable throughout the use. Compensation for liner wear is easily done by increasing the spring tension. The design of brake motor facilitates a very easy replacement of armature disc and brake liner assembly.

   

• For crane and hoist duty applications Brake Motors are offered with special rotors.These rotors are specially suited for S₃ and S₄ duty normally encountered in hoist and crane applications.

   

Applications:
Brake Motors are used for numerous applications. A few of them are listed below: