Motor Characteristics

The speed-torque relationship of a DC motor describes how the speed of the motor varies with load torque. This is known as the Mechanical characteristic of the motor. It helps in understanding motor behavior under different loading conditions and is important for designing motor-driven systems. The electrical characteristic, in contrast, refers to current-voltage relations.

Shaded pole motors are simple and inexpensive types of single-phase induction motors. They are typically manufactured with power ratings between (frac125) HP (horsepower) to (frac16) HP. This makes them suitable for low-power applications such as small fans, hair dryers, and other household appliances. Their construction is simple with low starting torque, and they are not used for higher power ranges like 3 HP to 10 HP, which require more robust motor types.

Manual handling causes over a third of all workplace injuries. hfill True
textitExplanation: Manual handling is a major cause of workplace injuries due to strain and improper lifting.
Maintenance cost of slip ring motor is less as compared to squirrel cage motor. hfill False
textitExplanation: Slip ring motors have higher maintenance costs because of brushes and slip rings.
Always place transformer in a dry area. hfill True
textitExplanation: Transformers should be kept in dry areas to prevent moisture damage and insulation failure.
The core of electromagnet is made up of soft iron or silicon steel lamination. hfill True
textitExplanation: Soft iron or silicon steel laminations reduce eddy current losses in electromagnet cores.
Three-phase induction motors are used for domestic purposes. hfill False
textitExplanation: Single-phase induction motors are typically used for domestic appliances; three-phase motors are used industrially.
DC series motor is used when high starting torque is required. hfill True
textitExplanation: DC series motors provide high starting torque and are used in applications like cranes and hoists.