Desirable characteristics of ideal traction motors:-
A) Mechanical Properties or characteristics: 1) It should be robust in construction to withstand against continuous vibrations. 2) Weight of motor per HP should be minimum in order to increase pay load capacity. 3) It must be small in overall dimensions, especially in overall diameter. 4) It must have totally enclosed type enclosure to provide protection against entry of dirt, dust, mud, water etc. in drive. 5) When motors are running in parallel they should share almost equal load. (even when there is unequal wear & tear of driving wheels)
B) Electrical Properties or characteristics: 6) It should have high starting torque. 7) It should possess high rate of acceleration & retardation. 8) It should be variable speed motor. 9) Its speed-torque characteristics should be such that it should producehigh torque at low speed and low toque at high speed. 10) Motor must be capable of taking excessive overload in case of emergency. 11)It should have simple speed control methods. 12) Electrical braking system should be reliable, easy to operate and control, especially regenerative braking is possible. 13) Motor should draw low inrush current (Starting current,and if supply is interrupted and restore again.) 14)It should withstand for voltage fluctuation without affecting its performance.
C) General Properties or characteristics: 19) It should have low initial cost. 20) It should have less maintenance cost. 21) It should have high efficiency. 22) It should have long life.
Some of the motors which find application are- 1. DC Series Motor 2. 1-Ph, AC series motor 3. 3-Ph, Slip-ring induction motor 4. Linear induction motor (LIM)