Product Description:

The 2VM61-020-13 is a permanent-magnet DC servomotor produced by Pacific Scientific within the Low Inertia PMDC Servomotors series. In positioning or speed-regulated axes, the unit supplies torque with low rotational inertia so control loops can accelerate and decelerate rapidly without excessive overshoot. It is intended for fixed-voltage drive systems that require a compact motor body and an integrated tachogenerator for velocity feedback. By combining an Alnico magnetic circuit with a two-inch frame, the motor suits semiconductor handlers, small pick-and-place heads, and other light mechanical loads used in automated assembly cells.

The cylindrical steel housing has a body outside diameter of 2.700 in and an overall stack length of 5.429 in, dimensions that permit mounting in tight mechanical spaces while keeping the magnetic gap uniform. Alnico V magnets supply a fixed flux field, so armature current alone determines output torque. Because the design does not use forced-air cooling, heat leaves the frame by convection and conduction; under continuous duty, the winding can dissipate 59 W without exceeding its rated temperature rise. An optical encoder is not fitted, so velocity feedback comes from the rear-mounted tachogenerator. That tach has a rotor measuring 2.765 in in diameter and adds an inertia of only 0.00005 oz-in-s², minimizing the load seen by the control loop and preserving the low-inertia response associated with this series.

The tach section provides electrical feedback values used for drive tuning. The tach coil has 50 Ohms of resistance, a value that balances signal strength and power loss. Its output remains linear within ±0.5% of output across the rated speed range, so velocity error stays predictable. A voltage constant of 2.5 V/kRPM ±5% provides a proportional signal for straightforward scaling in analog or digital drives, and peak-to-peak ripple is limited to 1.5% p-p Max, so additional filtering is usually unnecessary. The 2.062 in tach length keeps the overall package compact while still allowing standard mounting flanges and connectors.