240D25-17 Datasheet, PDF (12/12 Pages) List of Unclassifed Manufacturers – SOLID-STATE RELAYS

DATA SHEET
Form 859-990514
SOLID-STATE RELAYS
page 12/12
Applications
Tips (Continued)
Single-Phase Reversing Motor Control
The circuit diagram illustrates a typical 1 Ø motor winding inductance and the phase shift
capacitor can cause twice line voltage to appear across the open SSR. A 240-volt SSR should be
used for a 120-Volt line. During the transition period when one SSR is turned on and the other
SSR is going off, both SSRs may be on. In this case, the capacitor may discharge through the
two SSRs, causing large currents to flow, which may destroy the SSRs. The addition of RL as
shown will protect the SSRs from the short circuit capacitor discharge current.
CALCULATE RL as: RL =
1.4 EAC
10 x SSR full load rating
EXAMPLE: 10 amp SSR
120 V AC Line
RL =
1.4 x 120
10 x 10
= 1.7 ohm
The resistors are unnecessary if the
control circuit is designed to ensure
one SSR is off before the other SSR is
on.
Three-Phase Motor Control
Three-Phase Reversing Motor Control
Three-phase motors may
be controlled by solid-state
relays as shown. A third
SSR as shown is optional,
but not necessary. The
control windings may be
connected in series or
parallel. Care should be
taken to ensure that surge
current drawn by the motor
does not exceed surge
current rating of the SSR.
240-Volt 3θ Motors
SSR MODEL MOTOR
Z240D25
1/3 HP
Z240D10
3/4 HP
240D10
3/4 HP
240A10
3/4 HP
240D25
2 HP
240A25
2 HP
240D45
3 HP
480-Volt 3θ Motors
SSR MODEL MOTOR
480D10-12 1-½ HP
480D15-12 1-½ HP
Three-phase reversing motor control can be implemented with four
SSRs as shown in the connection diagram. The SSRs work in pairs
with SSR1 and SSR3 operated for rotation in one direction and SSR2
and SSR4 operated for rotation in the reverse direction. The
resistor R1 as shown in the connection diagram protects against
line-to-line shorts if SSR1 and SSR4 or SSR3 and SSR2 are on at
the same time during the reversing transition period. Use the
following table as a guide to the proper selection of an SSR for
this application.
Opto 22
Relay
3-Amp
10-Amp
25-Amp
45-Amp
15-Amp
Motor
Full Load
Rating
1.25-Amp
5-Amp
8-Amp
16-Amp
5-Amp
Resistor for
120V line
4 ohm 50 W
1 ohm 100 W
.5 ohm 100 W
.25 ohm 150 W
1 ohm 100 W
Resistor for
240V line
8 ohm 50 W
2 ohm 100 W
1 ohm 100 W
.5 ohm 150 W
2 ohm 100 W
Opto 22 • 43044 Business Park Drive • Temecula, CA 92590 • Phone: [phone] • (800)321-OPTO • Fax: [phone] • Internet: www.opto22.com
Inside Sales: (800)452-OPTO • Product Support: (800)TEK-OPTO • [phone] • Fax: [phone] • E-mail: [e-mail] • FaxBack: (800)474-OPTO
All products and/or company names throughout this datasheet are generally trademarks or registered trademarks of their respective companies.