Product Description:

The SR3720-3798-7-56C direct-current unit is manufactured by Pacific Scientific as part of the Permanent Magnet DC Motors series. It is a permanent-magnet DC motor intended for variable-speed or constant-torque duties in automated conveyors, mixers, and small positioning systems. The motor uses a 56C frame for interchange with standard gearheads, and its totally enclosed nonventilated housing keeps cooling air outside the windings, helping prevent dust intrusion in harsh plant environments.

From an electrical standpoint, the motor is designed for a supply of 90 VDC and draws a continuous armature current of 2.5 A. These values place it in the fractional-horsepower category that pairs with compact SCR drives, and its drive compatibility is listed as SCR-rated, meaning the armature can tolerate the pulsating voltage produced by single-phase controlled-rectifier regulators. The unit is wound as a permanent-magnet field device, so no shunt excitation is required, and commutation occurs through a brush set sized to handle the stated current. A standard C-face registration ring keeps the shaft concentric to the mounting pilot, helping reduce radial misalignment when the motor is coupled to a speed reducer. Four threaded mounting holes complete the interface, using a 4 × 3/8-16 UNC-2B pattern to secure the motor to the driven equipment.

Mechanical output is delivered through a shaft with a diameter of 0.6250 in and an extension length of 1.875 in. The shaft includes a rectangular key measuring 0.188 × 1.38 in to transmit torque without slip. The face of the housing provides a bolt circle of 5.875 in, while the pilot registers at 4.500 in to center the motor in mating machinery. These dimensions align with standard NEMA 56C mounting geometry and support direct installation in compatible equipment. The enclosed design also reduces the need for airflow clearance around the stator, so the motor can be mounted in tight conveyor tunnels or other enclosed machine spaces.