Relay Contact Resistance
Contact resistance is a crucial electrical characteristic. The resistance between the contact terminals determines the Relay's ability to carry current. The contact resistance is subject to change during the life of the Relay. Based on lab investigations and testing, abnormal contact resistance has often been found with the following conditions:
Most of Panasonic's electromechanical Relays have a specified contact resistance value of 100 mOhms (Max):
|Arrangement||1 Form A||1 Form C||1 Form A|
|Contact resistance (Initial)||Max. 100m Ω (By voltage drop 6 V DC 1 A)||Max. 100m Ω (By voltage drop 6 V DC 1 A)||Max. 100m Ω (By voltage drop 6 V DC 1 A)|
|AgSnO₂ type||AgSnO₂ type|
Measuring Contact Resistance
The standard method for measuring contact resistance is the 6Volt 1Amp method, sometimes referred to as four wire measurement. It is a simple method that can be easily implemented with two power supplies, and a digital voltage meter (DVM).
Standard Method For Measuring Contact Resistance
Example: If the DVM reading is 15 mV, then the resistance measurement is 15 mOhms.
This simple method of measuring contact resistance can turn out to be very helpful when performing a simple diagnostic investigation.
Check out Panasonic's electromechanical Relays and other products here.