Installation / Operation / Maintenance Manual
10/28/2019
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6.
TIMING RELAYS
The following Timing Relays are used on Lake Shore Automatic Transfer Switches.
Timing Relay
Factory Setting
Time of Delay
Function
.
T
10 Seconds
On Delay
Time Delay to Transfer to Normal
TNR
10 Seconds
Off Delay
Time Delay to Transfer to Emergency
P
10 Seconds
Off Delay
Time Delay to Alarm Circuit
TNR, P Relay
These relays are pneumatic. They are true OFF delay relay as no power is required for timing. When power is applied
to the relay coil the N.O. and N.C. contacts transfer. When power is removed from the relay coil the timing cycle starts.
After the timer has timed out the contacts will transfer to their original state.
7.
VOLTAGE RELAYS
7.1.
VOLTAGE SENSING – CLOSE DIFFERENTIAL
This relay continuously monitors the voltage of a three phase or a single-phase power source. When the voltage in each
phase attains a value equal to or greater than the "pick-up" setting, the output contacts change state and the L.E.D.
energizes. When the voltage of any phase falls below the "drop-out" setting, the output contacts revert to their de-
energized state and the "LED" turns off.
Pick-up and dropout values are adjustable from 70 to 100% of nominal voltage via two potentiometers that are
externally accessible.
FACTORY SETTING
Unless a customer or specifications require specific settings, the voltage Sensing Relay will be factory set to dropout at
80% and pick-up at 90% of nominal voltage.
LAKE SHORE ELECTRIC THREE PHASE STYLE
The Lake Shore voltage-sensing relay is field adjustable.
CALIBRATION:
1.
Select proper voltage range.
2.
Set pickup potentiometer full clockwise.
3.
Set dropout potentiometer full counter-clockwise
4.
Using a small screwdriver, turn the calibrate potentiometer fully clockwise.
5.
Apply nominal input voltage to unit.
6.
Slowly turn the calibration potentiometer counter-clockwise until the units picks up as indicated by the
"energized" light.
7.
Set pickup and dropout potentiometers to desired settings.
8.
Unit is ready for operation.
Note:
Field adjustment can only be considered approximate if potentiometers are set using the scale on the front of the
unit. For an accurate setting of the pickup and dropout points, a variable voltage power supply must be used.