Industrial Power Engineering Handbook

3

Duties of Induction Motors

Contents

Duty cycles

Continuous duty (CMR) (S₁)

Periodic duties

Short-time duty (S₂)

Intermittent periodic duty (S₃)

Intermittent periodic duty with start (S₄)

Intermittent periodic duty with start and brake (S₅)

Continuous duty with intermittent periodic loading (S₆)

Continuous duty with start and brake (S₇)

Continuous duty with periodic speed changes (S₈)

Non-periodic duty (S₉)

Duty with discrete constant loads (S₁₀)

Factor of inertia (FI)

Heating and cooling characteristic curves

Time constants

Heating curves

Cooling curves

Drawing the thermal curves

From cold conditions

From hot conditions

Rating of short-time motors

Equivalent output of short-time duties

Shock loading and use of a flywheel

Size of flywheel ...