Honeywell AUTOMATIC CONTROL, Engineering Manual

Page: 113 / 518

ENGINEERING MANUAL OF AUTOMATION CONTROL
ELECTRIC CONTROL FUNDAMENTALS
103
LINE VOLTAGE
T1
T2
C2512
THERMOSTAT
HIGH-LIMIT
CONTROLLER
ACTUATOR
TRANSFORMER
HOT WATER
SUPPLY
VALVE
TO
COIL
CONTROL COMBINATIONS
Series 80 control combinations are similar to those of
Series 40. The following applies:
1. Series 80 circuits require an external, low-voltage
transformer.
2. Series 80 equipment can be controlled by Series 40 or
80 controllers.
3. Series 80 controllers can control line-voltage actuators
or other line-voltage devices by using a Series 80 relay
with line-voltage contacts.
HIGH-LIMIT CONTROL
A Series 80 valve with high-limit controller is shown in
Figure 11. The transformer supplies 24V ac to the circuit. The
thermostat controls the heating valve actuator. The high-limit
controller opens the circuit on a temperature rise to the high-
limit setting. Contacts on both controllers must be closed to
open the valve.
Fig. 11. High-Limit Control of Series 80 Solenoid Valve.
LOW-LIMIT CONTROL
Same as for Series 40 except that a transformer and a
Series 80 actuator are used. See Figure 9.
SERIES 60 TWO-POSITION CONTROL CIRCUITS
APPLICATION
A Series 60 two-position control circuit is a line- or low-
voltage circuit which requires a single-pole, double-throw
controller to operate a reversible drive actuator. Series 60 two-
position control circuits can be used for open-closed control of
valves or dampers.
The basic Series 60 circuit contains a Series 60 actuator
and a Series 60 controller. Limit controllers can be added
where required.
EQUIPMENT
CONTROLLERS
1. Temperature controllers.
2. Humidity controllers.
3. Pressure controllers.
4. Any single-pole, double-throw controller such as a relay
or switch.
Series 60 two-position controllers are line-voltage rated
devices and have a spdt switching action that is obtained by
use of a mercury switch or snap-acting contacts. Series 60
controllers can operate line- or low-voltage devices.
ACTUATORS
Series 60 actuators consist of a low-voltage, reversible
motor which operates a gear train to rotate a drive shaft. The
actuator drives open and closed by switching voltage input to
the motor, not depending on a spring to close. Built-in limit
switches stop the motor at open and closed positions of the
actuator stroke. The drive shaft is mechanically connected to
the damper or valve by a suitable linkage. On power interruption
or loss of control signal, the actuator maintains its current
position between limits. This allows the actuator to be used in
either two-position applications or floating applications (see
SERIES 60 FLOATING CONTROL CIRCUITS).
Most Series 60 actuators have low-voltage motors. Line-
voltage models will often have a built-in transformer to change
the incoming line voltage to low voltage for the control circuit
and the motor. Low-voltage models require an external
transformer to supply voltage to the actuator. See Figure 12.
Some Series 60 actuators have line-voltage motors.