Siemens MT Series, SSC81.5U, Powermite 599, SSC81U, Powermite 599 MT Series SSC81U Technical Instructions

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Powermite 599

MT Series SSC Electronic Valve Actuator, 24 Vac Floating Control

Technical Instructions

Document No. 155-314P25

EA 599-16

May 10, 2011

Description

Features

Application

Product Numbers

EA1157R1

The Powermite 599 MT Series SSC81U and SSC81.5U electronic valve actuators require a 24 Vac supply to provide a floating control signal. These actuators control Powermite 599 MT Series valves with a 7/32-inch (5.5 mm) stroke and a threaded valve bonnet that fits the actuators.

• UL listed for plenum installations

• Direct-coupled installation without special tools (hand-tightened)

• Manual override

• Visual position indication

The Powermite 599 MT Series SSC81 electronic actuators and MT Series valves are used in heating and cooling applications. They are used in liquid and steam applications. The SSC81 series accepts plenum cable or 3/8-inch flex conduit connection.

Table 1. Product Numbers.

Actuator Operating Mode

Actuator Prefix

Code

Ordering a Valve Plus Actuator Assembly

To order a complete valve plus actuator assembly from the factory, combine the actuator prefix code with the suffix of the valve product number. See Technical Bulletin

TB251, Powermite 599 Series MT Series Terminal Unit Valve and Actuator Assembly Selection (155-306P25) for selection procedures.

To order an actuator only, use the product number.

SSC81U

SSC81.5U

Non-Spring Return

(Fail-in-Place) Spring Return

(Fail-Safe)

259

260

Siemens Industry, Inc.

Technical Instructions MT Series SSC Electronic Valve Actuator, 24 Vac Floating Control Document Number 155-314P25 May 10, 2011

Warning/Caution Notations

Specifications

Power requirements

Functional operation

Agency certification

Ambient conditions

Physical characteristics

WARNING:

CAUTION:

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

SSC81U power consumption 0.8 VA SSC81.5U power consumption 3 VA at ultra cap load,

2 VA at normal operation Running time

SSC81U 125 s ±2% at 60 Hz SSC81.5U 125 s ±2% at 50/60 Hz

Spring return, SSC81.5U only ( Nominal stroke 7/32-inch (5.5 mm) Nominal force 67 lb (300N) Stroke/signal relationship Linear Capacitor charge time ( Spring return (SSC81.5U only) Non-mechanical, electronic returns

to stem up (0 position) UL UL873 Listed cUL Certified to CSA

C22.2 No. 24-93 Ambient temperature

Operation 41°F to 122°F (5°C to 50°C) 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) 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 See

Personal injury or loss of life may occur if you do not perform a procedure as specified.

Equipment damage may occur if you do not follow a procedure as specified.

10 actuators with one transformer.

Figure 1, ) ≈ 30 s

Figure 1 ) max. 180 sec

Figure 10

Page 2 Siemens Industry, Inc.

MT Series SSC Electronic Valve Actuator, 24 Vac Floating Control Technical Instructions Document Number 155-314P25 May 10, 2011

Service Kits

411555648 For actuators with date

codes of 031215F or later. Kit contains:

- Terminal cover

- Cover screws-2 (not shown)

- Tailpiece

- Tailpiece screw-1 (not shown)

EA1156R1

EA1162R1

- Cable lock

- Terminal block-3

Operation

EA0851R1

EA1138R1

411656088 For actuators with date codes before 031215F. Kit contains:

- Terminal Cover

- Cable lock

- Cover screw- 1 (not shown)

EA0850R1

EA0851R1

A 24 Vac control signal to terminal Y1 extends the actuator shaft proportionately to the length of time the signal is applied.

A 24 Vac control signal to terminal Y2 retracts the actuator shaft proportionately to the length of time the signal is applied.

In the event of a power failure with no control voltage, the non-spring return SSC81U will hold its last position.

In the event of a power failure, the SSC81.5U returns to the stem up 0 position. The SSC81.5U includes an electronic return mechanism that functions as follows. See Figure 1.

• At power-up (t0), a capacitor must charge to its maximum capacity

(Max, tc). This will take a maximum of 180 sec, during which time no

actuator movement occurs.

• Once the capacitor is fully charged (tc), normal actuator operation

occurs.

• If a subsequent power failure occurs (tn) of greater than 5 seconds, the

TIME TO

CHARGE

Max

CHARGE

t0 tc tn t

MAX

EA0798R2

180s.

Figure 1. SSC81.5U Electronic Spring

Return Mechanism.

NORMAL

ACTUATOR

OPERATION

TIME

TIME TO

DISCHARGE

MAX

30s.

ACTUATOR

capacitor discharges (td) and the actuator spring returns to stem up 0

position.

POSITION

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