The selection of control gear for a particular application is based on the consideration of
Right Answer is:
All of the above
SOLUTION
The selection of control gear for a particular application is based on the consideration of Duty cycle, Limitation of starting current, starting torque.
Motor Selection
The first step in selecting a motor is the analysis of the requirements imposed by the application; these can be divided into three groups:
- Motor requirements
- Load requirements
- Control requirements.
The table given below summarizes the important considerations for each of these. On the basis of the requirements listed in Table, one can undertake the task of selecting a motor for a specific application.
Motor Requirement | Load Requirement | Control Requirement |
Operating speed | Determine worst-case operating conditions | Available power (AC, DC) |
Life span and maintenance | Dynamic acceleration, full-load and overload conditions | Motor operating voltage and current |
Torque characteristics | Starting conditions | Open- or closed-loop |
Mechanical aspects (size, weight, noise level, environment) | Transients | Forward/reverse operation |
Applicable standards (e.g., radio frequency interference) | Need for gearing, selection of optimum gear ratio | Motoring and/or braking |
Overload characteristics | Frictional characteristics | Torque, position, or speed control |
Thermal dissipation characteristics | Accuracy of speed or position control |
The selection of an electric motor for any application depends on the following factors:
Selection of Electric Motor for any application
- Electrical characteristics
- Running characteristics
- Starting characteristics
- Speed control
- Braking characteristics
- Mechanical characteristics
- Power transmission
- Cooling
- Noise
- Type of enclosure
- Size and Rating of motors
- Load cycle
- Continuous
- Intermittent
- Variable
- Overload capacity
- Load cycle
- Cost
- Initial cost
- Cost of control gear
- Running cost
For a particular application, the type of electric drive and control gear determines by the following considerations:
- Starting torque
- Duty (whether light, medium, heavy)
- Limitations on starting current
- Speed control range and its nature
- Need for automatic control
- Conditions of environment