A gearmotor is a homogeneous and compact unit consisting of a gear unit and a motor.
AC gearmotors are an economical, easy-to-use choice for fixed-speed or variable-speed velocity control applications. Winding options include AC fixed speed, PSC (permanent split capacitor) or split-phase (single-phase) windings, or the more popular variable-speed AC three-phase, inverter-duty windings. Because there are fewer moving parts and no brushes to replace, AC gear motors are a cost-effective, maintenance free, and simple drive solutions for many industrial applications such as conveyor systems, food processing equipment, medical equipment and factory automation. AC gearmotor styles are: parallel shaft, planetary/inline, hollow shaft and right-angle worm gearmotors, with rated power from 1/25-3/4HP, gear ratios from 5:1 to 3600:1, and rated torque up to 1000 lb-in (113 Nm).
Bodine permanent magnet DC (PMDC) and Brushless DC (EC) gearmotors provide quick acceleration, and deceleration, easy reversing, and high starting torque. PMDC gear motors also offer predictable performance because the output torque of a PMDC geared motor is directly proportional to its input current, and the gearmotor output speed is directly proportional to the applied voltage. A PMDC gearmotor-and-control drive system often costs less than comparable inverter-duty AC geared motors and drives.
12 and 24 VDC gearmotors are ideal for low-voltage applications driven by batteries or solar power supplies, and are frequently used in mobile, portable and off-grid equipment. Due to their high starting torque, PMDC gearmotors are also frequently found in applications where the load is highest during start-up, such as conveyors and mixers. Bodine parallel shaft, hollow shaft, right-angle and Hypoid PMDC gearmotors are rated from 1⁄4 to 1/2 HP, with speed from 0.7 to 658 rpm and rated torque up to 1535 lb-in (173 Nm).
What is a Gearmotor?
Gearmotors (also called geared motors or gear motors) are small electric motors designed with an integral (non-separable) gear reducer (or “gearhead”) attached to the AC, PMDC or BLDC motor. Gearmotors function as torque multipliers and speed reducers, requiring less motor power to drive a given load. The gear housing design, the gearing type, gear lubrication, and the specific mode of integration all affect the gearmotor performance and life.
This integral gear motor design eliminates the need for motor and gearhead couplings, it eliminates the risk of possible motor and gearhead misalignment, and it eliminates the guesswork of sizing a motor and gear reducer for the user. The key design feature of a small integral gearmotor is that the motor end shield (blue) at the drive end of the motor is designed to provide a dual function:
The end shield side facing the motor provides the armature/rotor bearing support and a sealing provision through which the integral rotor or armature shaft pinion passes.
The side of the end shield that is facing the gearhead provides multiple bearing supports for the gearing, and a sealing and fastening provision for the gear housing.
There are two main styles of gearboxes: those with output or drive shafts that are oriented parallel or inline to the motor armature or rotor shaft, and those with output or drive shafts that are oriented at a 90° or right-angle to the motor shaft.
Parallel Shaft Gearmotors (AC or DC)
Parallel shaft gearmotors are also called “inline offset” gear motors. These gearmotors reduce the motor speed (typically from 1700, 2500 or 3400 rpm) to as low as 0.4 rpm, and as high as 550 rpm. Common winding options are AC fixed speed PSC or split-phase, or the more popular variable-speed AC three-phase, inverter-duty designs. DC gearmotors are either driven by permanent magnet DC (PMDC) or brushless DC (BLDC) motors. In general, parallel shaft gearmotors have a higher output torque, efficiency, and lower backlash than right-angle worm gearmotors.
Planetary/Inline Gearmotors (PMDC or BLDC)
Planetary gearmotors are integral gearmotors with the motor shaft in-line with the gearhead output shaft. A planetary gearhead is comprised of the motor pinion acting as the “sun” gear, a ring gear, and a planet carrier assembly that uses three to five planet gears. The output shaft is attached to the planet carrier of the output stage. Planetary gear motors deliver higher torque and lower backlash than other parallel shaft (spur or helical gear) gearmotors of equivalent size.
Right-Angle and Hollow Shaft Gearmotors (AC or DC)
The output shaft of a right-angle (or hollow shaft) gear motor is at a 90-degree angle from the motor shaft. Bodine right-angle gearmotors feature either worm gearing or hypoid gearing. Worm gearboxes are a proven and economical solution for applications that require high speed-reductions in limited space, and with very smooth and quiet operation.
Hollow shaft right angle gearmotors can be used in either left-hand or right-hand installations, and eliminate the need for sprockets, pulleys or shaft couplings. Worm gears have inherent self-locking ability depending on design and ratio. All Bodine right-angle worm gearmotors are permanently lubricated with high-performance lubricant, and feature bronze gears for high shock load capability. The worm gear is hardened and ground for high strength and long life. Right angle Hypoid PMDC hollow shaft gearmotors have several advantages when compared with standard worm-and-wormgear right-angle gearmotors. While more costly to manufacture, hypoid gearmotors are more efficient, produce less heat, provide higher torque, and are usually smaller than equivalent gearmotors with worm-and-pinion reducers.