Glossary of Terms

Ambient - The temperature of the space surrounding the motor.Generally, motors are designed to operate in a temperature of 40°C (104°F) or less.
Ambient Temperature - The temperature of the space surrounding the power transmission equipment during operation.
Automatic Reset - Thermal protector automatically reconnects power to motor following cooling period. Do not use in situation where unexpected restart would be hazardous.
Breakdown Torque - The maximum running torque of a motor without causing an abrupt reduction in speed and power.
Braking - The mechanical and/or electrical mechanism available to provide instant stopping or slowing of a motor or gearmotor to prevent or reduce over-travel. Depending on the type of brake selected it can also provide a degree of holding torque.
Capacitors - It is critical to operation performance and motor life to specify the correct capacitor with motor selection. Capacitor ratings to HP ratings will vary with different brands and applications. Merkle-Korff will recommend the correct capacitor to meet your requirements.
Coupling Load to Shaft - Consider the form of coupling with the configuration and machining of the output shaft. Always specify if a pulley is to be used. Optimum designs locate the load nearest to the gearcase output bearing.
Custom - DC Motors and Gearmotors customized to applications requiring a specific torque, speed and shaft configuration.  Merkle-Korff also offers a wide range of "stock" products for consideration.
Duty Cycle - The relationship between operating and rest time.
Full-Load - The minimal speed an induction motor operates under rated load output torque. Full load will vary depending upon the rating and characteristics of the specific motor and will be less than the synchronous speed.
Full-Load Amps - Amperage drawn by motor operating at rated output torque and voltage.
Hertz - Frequency of AC power in cycles per second. Usually 60 Hz in USA, 50 Hz overseas.
Impedance Protected - Under locked rotor or stalled condition, motor is thermally protected via motor winding impedance to prevent burnout per UL standard No. 519.
Motor Types - Classified by operating characteristics and power specified. For example Shaded Pole, Permanent Split Capacitor, and DC.
Mounting - The mounting position may affect shaft loading and the performance of the optional motor brakes. The relative position of the gearmotor to the application will dictate certain design parameters. (See Basic Specification Form).
Output Speed - Speed as rated in revolutions per minute (rpm) in a full load condition or a free running condition. Rated frequency of the associated voltage will affect overall output speed.
Overhung Load - The side or radial force applied at right angles to a drive motor, gearmotor or reducer shaft. The bearing and shaft must support this force while transmitting power.
Permanent Split Capacitor - Low starting torque (similar to Shaded Pole) with low line current and high HP capabilities.
Radial Load - Interchangeable with the term "Overhung Load".
Reversible - Reversing motor for alternating current applications with low current draw.
Rotation - Direction in which shaft rotates clockwise, counter-clockwise or reversing.
Shaded Pole - An economical motor consisting of steel laminations, a wound electrical field coil, small copper shading coils and a rotor body. Merkle-Korff offers both high starting and high running torque models.
Sleeve Bearings - Important when low noise is critical. Can be mounted in any position, shaft-up or shaft-down.
Starting Torque - The maximum torque (turning ability) produced on start of motor.
Stock - Merkle-Korff has standing inventory meeting customer speed, torque, and shaft specifications.
Temperature Rise - The temperature degrees, above its surroundings, at which motor is operating. Check motor nameplate for ambient rating.
Thermal Protector - The automatic shut-off device, built into the motor, that senses excessive temperature due to overloading or start failure.
Torque - Typically measured in inch-pounds, torque is the twisting force applied to the output shaft of a motor or gearmotor.
Torque Load - The maximum torque produced by a running motor without a sudden decrease in speed and power.
Voltage - The amount of force or pressure pushing an electric current through a circuit.

Abbreviations: Motors & Gearmotors