Publication 700-AT001A-EN-E June 2002
2-16
Considerations When Designing SSR Control Systems
Temperature Control of an Electric Furnace
Forward and Reverse Operation of a Single-phase Motor
Note: The voltage between the load terminals of either SSR 1 or SSR 2 turned OFF is approximately twice as high as
the supply voltage due to LC coupling. Be sure to apply an SSR model with a rated output voltage of at least
twice the supply voltage.
1
For example, if the motor operates at a supply voltage of 100 V AC, the SSR must have an output voltage of 200
V AC or higher.
2
Make sure that there is a time lag of 30 milliseconds or more to switch over SW1 and SW2.
ON/OFF Control of a Three-phase Inductive Motor
Single SSRs in Combination
Input signal
source and
Temperature
Controller
Load
heater
Load po
w
er supply
INPUT
Fuse or
breaker
Motor
Load po
w
er supply
C
Fuse or
breaker
Motor
Three-
phase
power
supply
Input signal
source
Fuse or
breaker
R
S
T
