What protection devices are used for electric motors?

Motor protection includes: overload relays (thermal or electronic, protect against sustained overcurrent), fuses/MCCBs (short circuit protection), ground fault protection (detect earth leakage), undervoltage relays (prevent starting or cause trip during low voltage), phase loss protection (prevent single-phasing), thermistors/RTDs (direct temperature sensing in windings), and locked rotor protection (detect stalled condition). Motor protection relays combine multiple functions with adjustable settings and diagnostics.