Servo Shop is responsible for maintaining the electronics on
the motors that point the antennas. Each antenna at the VLA and the
VLBA has 4 motors: 2 for azimuth and 2 for elevation. These motors
generally work against each other to provide precision pointing to
less than 10 arc seconds.
The VLA motors have been running since the 1970s and are pretty
robust. The VLBA antennas tend to be more sensitive to power
glitches and often blow fuses. Tom and Ken give the VLBA site
technicians technical assistance over the telephone if they need
immediate servo help.
Servo motors weigh 300 lbs. The antenna mechanics remove and
refurbish them. The motors are then sent to the Servo Shop for work
on the electronics. The shop has both a VLA and a VLBA simulator for
testing the units before they are re-installed on the antennas.
The armature fits inside the motor.
Tom points out the rotor end.
The Servo Shop also works on ACUs-Antenna Control Units. The ACUs convert commands from the modcomps (computers that control the antennas) to electrical motor currents that point the antenna for the observer.
They test the ACU and servo drive
cabinet-safety interlocks. It provides current to motors
to move antennas. Secondly, it controls the interlocks for safety of
personnel and antenna.
Servo also provides technical support for
the visitor center exhibits. They keep the Small Radio Telescope in
good working order.
National Radio
