Product Overview

Technical Instructions MT Series SSC Electronic Valve Actuator, 24 Vac Floating (3-Position) Control
Document Number 155-314P25
August 1, 2007
Page 2 Siemens Building Technologies, Inc.
Specifications
Power requirements
Operating voltage 24 Vac ±20%
Frequency 50/60 Hz ±2 Hz
Power supply Earth ground isolating, Class 2,
24 Vac transformer
NOTE: Do not power more than
10 actuators with one
transformer.
SSC81U power consumption 0.8 VA
SSC81.5U power consumption 3 VA at ultra cap load,
2 VA at normal operation
Control characteristic
Control Signal
Y2 Retracts actuator shaft
Y1 Extends actuator shaft
G System potential
G0 (SSC81.5U only) System neutral
Functional operation
Running time
SSC81U 150 s ±2% at 50 Hz
125 s ±2% at 60 Hz
SSC81.5U 125 s ±2% at 50/60 Hz
Spring return, SSC81.5U only (Figure 1, ) ≈ 30 s
Nominal stroke 7/32-inch (5.5 mm)
Nominal force 67 lb (300N)
Stroke/signal relationship Linear
Capacitor charge time (Figure 1 ) max. 180 sec
Spring return (SSC81.5U only) Non-mechanical, electronic returns
to stem up (0 position)
Agency certification
UL UL873 Listed
cUL Certified to CSA
C22.2 No. 24-93
Ambient conditions
Ambient temperature
Operation 41°F to 122°F (5°C to 50°C) with
Transport and storage -13°F to 158°F (-25°C to +70°C)
Ambient humidity 0 to 90% rh (non-condensing)
Media temperature 41°F to 248°F (5°C to 120°C)
Physical characteristics
Wiring Connection Plenum cable or 3/8-inch flex conduit
Weight
SSC81U 1.1 lb (0.5 kg)
SSC81.5U 1.3 lb (0.6 kg)
Dimensions 5.5-in × 4.35-in × 2.0-in
(140 mm × 110,6 mm × 48 mm)