240A25 OPTO 22, 240A25 Datasheet - Page 15

• Manufacturer Part Number: 240A25
• Description: SSR, PANEL MOUNT, 280VAC, 280VAC, 25A
• Manufacturer: OPTO 22

Specifications of 240A25

• Control Voltage Range: 85VAC To 280VAC
• Operating Voltage Range: 24VAC To 280VAC
• Load Current: 25A
• Isolation Voltage: 4000Vrms
• Control Voltage Type: AC
• Relay Terminals: Screw
• Brand/series: AC Series
• Current, Rating: 25 A
• Current, Surge: 250 A (Max.)
• Dimensions: 1.75 in. W x 2.25 in. H x 0.77 in. T
• Function: Power
• Mounting Type: PCB
• Relay Type: Solid State
• Standards: UL, CSA, CE
• Termination: Quick Connect
• Voltage, Control: 240 VAC
• Voltage, Drop, On-state: 10 VAC
• Peak Surge Current: 250A
• Rohs Compliant: Yes
• Control Voltage Max: 280V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Applications: Tips
Heat Sink Calculation
Like all semiconductor devices, SSR current ratings must be based on maximum internal junction temperature. All Opto 22 SSRs
operate conservatively at maximum internal junction temperatures of 110 °C. Use the equation below to calculate the maximum
allowable heat sink thermal resistance for your application. It is good engineering practice to provide a margin for error instead of
running the application right at the limits. If your application is near the thermal limit, it can be helpful to add a fan to move air
across the heat sink.
IMPORTANT: Thermally conductive grease must be used between the relay base and the heat sink.
Sample Calculation 1
120-volt, 20-amp load; 50 °C ambient air temperature
Model: 120D25 SSR.
See the last two columns of the table on
the bottom of the table.
Dissipation: 1.3 watts/amp
Thermal resistance: 1.2 °C/watt
Maximum junction temperature: 110 °C
The calculation would be as follows:
© 2006–2011 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.
Solid-State Relays
800-321-6786 • 951-695-3000 • FAX [phone] • [e-mail] •
page 4
for thermal resistance and dissipation values for the 120D25. Also, see the note at
Opto 22 • 43044 Business Park Drive • Temecula, CA 92590-3614 • www.opto22.com
This calculation indicates that you
should select a heat sink with a thermal
resistance of less than 1.1 °C/watt.
800-835-6786 • 951-695-3080 • FAX [phone] • [e-mail]
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