Steps to Selecting a Relay
Follow the steps below to select the correct electromechanical (EMRs) or solid state relay (SSRs) for your applications.
1. Step 1. Identify mounting type:
a. Panel
b. DIN Rail
c. Plug-in
d. PCB
2. Step 2. Identify Required Load Voltage Rating & Type:
a. AC or DC
b. Determine maximum voltage to be switched
3. Step 3. Identify Required Load Current Rating:
a. Calculate Average Load current
b. Calculate Surge (inrush) current
4. Step 4. Identify required circuit/switching arrangement:
a. Number of poles/circuits to be switched
b. Normally Open, Normally Closed or
c. Changover switching function
5. Step 5. Identify Required Control Voltage & Type:
a. AC or DC
b. Control Voltage Range
6. Step 6. Identify Load Type:
a. Inductive (Random Turn-on SSR)
b. Resistive (Zero Crossing SSR)
7. Step 7. Identify Type of SSR Required:
a. Standard
b. Special Application:
i. Phase Angle Control
ii. Burst Fire Control
iii. Soft/Start Capability
8. Step 8. Use above parameters to identify a relay (electromechanical or solid state) matching maximum load voltage, maximum surge current, load type, control voltage, type & mounting requirements.
9. Step 9. Determine the amount of heat to be dissipated & select suitable thermal management solution.
1. Step 1. Identify mounting type:
a. Panel
b. DIN Rail
c. Plug-in
d. PCB
2. Step 2. Identify Required Load Voltage Rating & Type:
a. AC or DC
b. Determine maximum voltage to be switched
3. Step 3. Identify Required Load Current Rating:
a. Calculate Average Load current
b. Calculate Surge (inrush) current
4. Step 4. Identify required circuit/switching arrangement:
a. Number of poles/circuits to be switched
b. Normally Open, Normally Closed or
c. Changover switching function
5. Step 5. Identify Required Control Voltage & Type:
a. AC or DC
b. Control Voltage Range
6. Step 6. Identify Load Type:
a. Inductive (Random Turn-on SSR)
b. Resistive (Zero Crossing SSR)
7. Step 7. Identify Type of SSR Required:
a. Standard
b. Special Application:
i. Phase Angle Control
ii. Burst Fire Control
iii. Soft/Start Capability
8. Step 8. Use above parameters to identify a relay (electromechanical or solid state) matching maximum load voltage, maximum surge current, load type, control voltage, type & mounting requirements.
9. Step 9. Determine the amount of heat to be dissipated & select suitable thermal management solution.
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