4Pelco Manual C325M-C (6/99)
2.0 DESCRIPTION
Pan/tilts in the PT550P Series are designed to remotely position a TV camera in
both the horizontal and vertical attitudes. Pan (horizontal) and tilt (vertical) move-
ments are caused by activating small DC motors in the pan/tilt unit. All Pelco units
are equipped with adjustable limits for both pan and tilt, and all motors are equipped
with electrical filtering circuits to suppress RF interference.
The drive motors employ a permanent magnet type of field. The voltages applied
to the armature can be varied in magnitude to change motor speed and are re-
versed in polarity to change the direction of movement.
Braking is accomplished by electrically short-circuiting the motor armature. During
normal operation, dynamic braking is accomplished in the control unit by short-
circuiting both sides of the armature to the supply common. When a pre-adjusted
limit is encountered during operation, limit switches remove the driving voltage and
apply a short circuit to the motor armature.

2.1 MODELS

PT550P Medium duty pan/tilt, 115 VDC
PT550P/FGP Medium duty pan/tilt, 115 VDC, with special speed gearing for
pan (9°/sec pan speed)
PT550P/HB Medium duty pan/tilt, 115 VDC, with blanket heater in cover. 75
watts total. 120 VAC.
PT550P/PP Medium duty pan/tilt, 115VDC, with position feedback modifi-
cation. Requires preset control or control having AZL option
(position indication meter).
PT550P/RAD Medium duty pan/tilt, 115 VDC, with radiation resistant wiring
and white epozy paint. Low level radiation resistant up to 106
rads

2.2 OPTIONS

FG/570 Special high speed gears — 9°/4.5° per sec pan/tilt speed.
(Reduces load to 20lb or 9.08 kg)
FGT/570 Special high-speed gearing for tilt — 4.5°/sec tilt speed.
(Reduces load to 20lb or 9.08 kg)

2.3 RATINGS

•NEMA Type 3R
•IP 32