Overheating Protection for Motors

UL 2111

1 Scope

1.1 The requirements in this standard cover:

a)    Impedance-protected motors;

b)    Thermal-device-protected motors;

c)    Thermal-protective devices; and

d)    Motors with solid state thermal protection circuitry.


1.1 revised March 28, 2001

1.2 The requirements in this standard apply only to motors rated 600 V or less.

1.3 The requirements in this standard do not cover:

a)    A manual device for opening the circuit;

b)    A motor intended for use in a hazardous location;

c)    Motors employing a device that serves as a motor protector and a manual motor controller;

d)    Motors employing a motor protector with contacts that control a relay coil in a motor starter;

e)    Motors protected by devices responsive to current only;

f)    Sealed (hermetic) type motor compressors;

g)    Impedance-protected motors employing an automatic-starting switch; or

h)    Thermal cutoff devices. Thermal cutoffs are covered by the Standard for Thermal-Links - Requirements and Application Guide, UL 60691.


1.3 revised January 27, 2006

1.4 The requirements in this standard are intended to evaluate a specific motor, protector, and motor/protector combination. When either the motor, the protector, or the motor/protector combination is changed, a separate evaluation is required.

1.4 revised March 28, 2001

1.5 A product that contains features, characteristics, components, materials, or systems new or different from those covered by the requirements in this standard, and that involves a risk of fire or of electric shock or injury to persons shall be evaluated using appropriate additional component and end-product requirements to maintain the level of safety as originally anticipated by the intent of this standard. A product whose features, characteristics, components, materials, or systems conflict with specific requirements or provisions of this standard does not comply with this standard. Revision of requirements shall be proposed and adopted in conformance with the methods employed for development, revision, and implementation of this standard.

1.5 revised March 28, 2001