Rectifier Selection – Heavy Inching in Crane Hoisting
In hoisting application, overexcitation rectifier is highly recommended irrespective of brake size or torque. Use of overexcitation rectifiers prevents negative wear on friction liners, while motor is starting. DC switching must be carried out which will prevent slipping of the load. This applies for applications in which load will be influenced by gravity or requires to be stopped frequently. Also applicable for the brake motors run on VFD.
Over excitation rectifiers must be used,
- When braking torque is more than 100 Nm.
- When brake is used in hoisting application, with DC switching as mandatory, irrespective of braking torque value.
- When brakes are used for critical operating times, with DC side switching, irrespective of braking torque value.
- All over excitation rectifiers are of Half Wave Type.
- Most importantly, using over excitation rectifier saves drive system as it
- Helps in quick brake release.
- Improves operating times.
- Avoids Negative wear on the friction liner
- Avoid increase in motor current while starting of the motor, due to brake.
Rectifiers with standard excitation output voltage are not recommended if braking torque exceeds 100 Nm.
All rectifiers are having 6 terminals.
There are 2 kind of Rectifiers – Full Wave & Half wave.
For Full wave rectifier Output DC voltage = Input AC voltage x 0.9
For Half wave rectifier, Output DC voltage = Input AC voltage x 0.45
We offer full range of Emco Dynatorq Usha Medisales Over excitation & Standard excitation rectifiers. These are suitable for 2 Amps current rating. These are the natural choice as they are individually tested.. 100% of them are tested.50 cycles of ON/OFF operations for each unit is carried out as part of Test.Most importantly, these rectifiers are designed for dedicatedly Brake application only.High quality imported components adhering to German design are being used in its making..