H2W Technologies LCAM 5/15 Operation & Service Manual - Introduction
H2W Technologies, Inc., 26470 Ruether Ave. #102, Santa Clarita, CA 91350, U.S.A. (888) 702-0540
4
INTRODUCTION
The H2W Technologies LCAM 5/15 H bridge linear servo amplifier provides the optimum solution
for applications which require high current loop bandwidth, low radiated electrical noise and low
crossover distortion. This amplifier is constructed using surface mount technology and incorpo-
rates the latest in heat transfer technology which makes it one of the most powerful amplifiers for
a given form factor.
Typical applications are brushed DC permanent magnet motors and voice coil motors.
The LCAM 5/15 is configurable and can operate in the following modes:
1. Velocity mode for motors with tachometer feedback.
2. Current mode for torque mode operation.
A basic velocity mode servo loop for a brush type motor is shown in figure A. An external
controller commands a given velocity (RPM). The velocity loop summing amplifier compares this
command with the actual motor velocity, supplied by a DC tachometer on the motor shaft, and
produces an error voltage proportional to the difference between the actual and commanded
velocity.
The velocity error is used to command motor current in the inner servo-loop. The current loop
summing amplifier compares the command current (velocity error) with the actual current in the
motor and produces an error voltage proportional to the difference between the actual and
commanded current.
Finally, the current error signal is used to produce an output to drive the motor.
The velocity loop may be bypassed, and an external current command fed directly to the current
loop. In this case, the external command signal controls the torque of the motor, rather than the
velocity. This is known as current-mode operation.
Figure A - Velocity mode servo loop for a brush type motor