Samlexpower STS-30 Owner's Manual - page 6
6
3
INSTALLATION
Features
-
Can be confi gured for generator / power cord connection or inverter / alternate source
connection
-
Multiple ¾” and 1” knockouts (7, Fig. 1) have been provided on all the sides for ease of
routing the input and output cables
-
Consists of heavy duty 110 VDC, Double Pole Double Throw (DPDT) relay for switching both
the Line and Neutral. (R1, Fig 2)
-
Internal DIP Switch ( SW1, Fig 2) for enabling or disabling delayed transfer to generator
-
Internal LED (LED1, Fig 2) for indicating energized condition of the transfer relay coil (R1, Fig
2) and for diagnostics
Operation of the Transfer Relay (Please see Fig 2)
Relay R1 is a Double Pole Double Throw (DPDT) relay and is used to switch power from one source to
the other. The relay coil is energized as soon as 110 VDC is fed to terminals T7 and T8. When the relay
coil is de-energized, the common contact terminals T1 and T2 are connected to the Normally Closed
(NC) contact terminals T5 and T6 respectively. When the relay coil is energized, the common contact
terminals T1 and T2 switch over to the Normally Open (NO) contact terminals T4 and T5.
The relay coil operates at 110 VDC. This voltage is generated and controlled by the circuitry located
on PCB1. 120 VAC is tapped from contact terminals T3 and T4, is rectifi ed and made available to the
relay coil terminals T7 and T8 through a time delay circuit. DIP Switch SW1 located on the PCB1 is
used to enable or disable the time delay circuit. When the Time Delay Circuit is enabled (SW1 in OFF
position (1). This is the factory preset position), 110 VDC control signal for energizing the relay coil is
delayed by around 20 to 25 sec from the time 120 VAC is made available at the NO contact terminals
T3 and T4. When the time delay circuit is disabled (DIP Switch in ON position), the 110 VDC control
signal for energizing the relay coil is made available to terminals T7 and T8 as soon as 120 VAC is
made available at the NO terminals T3 and T4.
As soon as the 110 VDC control signal is fed to the relay coil to terminals T7 and T8, the green LED 1
lights up indicating that the relay coil has energized.
The delay of around 20 to 25 sec is required when the AC load is transferred to the generator. The
generator should never be started on load. Also, the generator takes around 20 to 25 sec to stabilize
in voltage and frequency.
Safety Instructions
-
Connections for stand by / backup power to a building / RV system using the transfer switch
must be made by a qualifi ed electrician and must comply with all applicable laws and
electrical codes.
-
Before starting installation, disconnect all live sources or power. Make sure that the generator
is off, the external shore power cord is unplugged, and the inverter, if any, is shut off.
-
The unit is not weather proof and should be mounted in a cool, dry and protected
environment.
-
To prevent exposure to foreign contaminants, do not mount the transfer switch in an engine
compartment, under kitchen sink drains or water pipes, within the battery compartment, or
in any compartment designed for storage of fl ammable liquids such as gasoline.