
BRAY Series 70 Tunnel Damper Electric Actuator
Operation and Maintenance Manual
3
inTrOduCTiOn
The Bray Series 70 Tunnel Damper Electric Actuator is
a quarter turn electric actuator with manual override
for use on any quarter turn valve requiring up to 5000
in.lb of torque. Operating speeds vary between 15 to 18
seconds.
PrinciPle OfOPeratiOn
The Series 70 Tunnel Damper electric actuator is divided
into two internal sections; the power center below the
switchplate, and the control center above the switchplate.
Below the switchplate the capacitor and gearmotor, with
its spur geartrain, drive a non-backdriveable worm gear
output. The override mechanism for manual operation
is also housed here. Above the switchplate is where user
required, readily accessible components are placed. The
camshaft assembly, limit switches, terminal strips, and
heater are all placed here for easy access. External to the
unit are adjustable mechanical travel stops, the unique
manual override handwheel, and dual conduit entry
ports. The external coating is a high quality polyester
powder coat which has exceptional UV as well as chemical
resistance.
electrical OPeratiOn
The motors used in the Bray Series 70 Tunnel Damper
electric actuator are permanent induction split capaci-
tor design (single phase AC power). Travel limit switches
are mechanical form ZZ(DPDT-DB) with contacts rated at
10 amp (0.8 PF), 1/2 HP 125/250 VAC. In cases where the
torque capacity of the unit is exceeded to the point where
the motor stalls and overheats, a thermal protector switch
built into the motor windings will automatically disconnect
the motor power. Once the motor cools sufficiently the
thermal protector switch will reset.
Mechanical OPeratiOn
Mechanically, the ratio of the gear motor determines the
speed of the unit. The gear motor utilizies high efficiency
spur gears. Initial gear reduction through the spur gears is
then transferred to the worm shaft. The final gear reduc-
tion and output is through a non-backdriveable worm gear
set. Positioning is determined by an indicator-cam shaft
linked to the output shaft. In the declutchable condition
the manual override drives the worm shaft when engaged.
cW vs ccW
Due to the fact that the Series 70 is a rotary actuator,
there are two directions that it can turn to actuate a
device: clockwise and counter-clockwise. Depending on
the application the actuator is going into, and the physical
constraints that application presents,itmay bepreferential
to designate which direction the actuator turns to open
and close. This is accomplished with the /Z designator,
which assigns the open direction of the actuator: CW for
clockwise and CCW for counter-clockwise. This can be
easily determined locally by looking at which direction
the open arrow is pointing on the actuator hand wheel,
and should be kept in mind when mounting the actuator
to the device. To ensure proper function, the direction of
travel should always align with the arrows on the hand
wheel and the /Z designator in actuator part number.
elevated teMPerature ratings
The Series 70 actuator is certified to meet NEMA type 4/4x
specifications. The actuator utilizes a thermally protected,
permanent split-capacitor (PSC) motor coupled to a gear
train, allowing operation after experiencing elevated
ambient temperatures. It has been tested to and complies
with NYCTA Master Specification 15ID dated 7/16/12 –
Dampers andAccessoriesforTunnelVentilation and Station
Smoke Management, certifying it for use after soaking at
an elevated ambient temperature of up to 302°F (150°C)
for a minimum of 1 hour without the use of an insulated
thermal blanket.
Part nuMbering systeM reference chart
series tOrque cOde sPeed PrOduct style vOltage triM dir
70 AAA W 113 X Y 536 /Z
hOusing
size Part nuMber tOrque
(In.Lbs)
sPeed, ¼turn
(Seconds)
suPPly
(Voltage)
12 70-0122-113E0-536 1200 15 120 VAC
12 70-0202-113E0-536 2000 15 120 VAC
30 70-0302-113E0-536 3000 18 120 VAC
30 70-0502-113E0-536 5000 18 120 VAC
Use this chart as a guide to interpret the S70 Tunnel Damper electric actuator part number.
W - DESIGNATES THE SPEED
215/18 seconds
X - DESIGNATES STYLE
EBasic Unit - Declutchable
Y - DESIGNATES THE VOLTAGE
0120VAC
/Z - DESIGNATES DIRECTION OF OPEN TRAVEL
/CW Clockwise
/CCW Counter-Clockwise