Home / General Topics / Can I run a 12v relay on 35v power supply ?

Can I run a 12v relay on 35v power supply ?

Running a 12V relay on a 35V power supply is generally not recommended, as it may exceed the relay’s specified voltage rating and lead to potential damage. Relays are designed to operate within a certain voltage range to ensure proper functionality and prevent overheating or failure. Here’s a detailed explanation:

  1. Voltage Rating of Relays:
    • Relays are typically rated for a specific voltage, such as 12V, 24V, or another standard value. This voltage rating indicates the nominal voltage at which the relay is designed to operate safely and reliably.
  2. Potential Issues:
    • Applying a voltage higher than the relay’s rated voltage can lead to several issues. Excessive voltage may cause the coil to draw more current than it is designed for, leading to overheating. This can result in damage to the coil winding or insulation, compromising the relay’s performance and lifespan.
  3. Coil Resistance:
    • Relays have a specified coil resistance, and the current flowing through the coil is determined by Ohm’s Law (I = V/R, where I is current, V is voltage, and R is resistance). If the applied voltage exceeds the rated voltage, the current will increase proportionally, potentially exceeding the relay’s safe operating limits.
  4. Potential Relay Failure:
    • Continuous operation of a relay with a voltage significantly higher than its rating can lead to premature failure. Over time, the increased stress on the coil and other components may cause degradation, affecting the relay’s ability to switch contacts reliably.
  5. Considerations for Overvoltage Protection:
    • If you find yourself needing to use a higher voltage power supply, consider using external circuitry to regulate the voltage applied to the relay. Zener diodes, voltage regulators, or resistors can be employed to limit the voltage across the relay coil within its acceptable range.
  6. Check the Datasheet:
    • Always refer to the datasheet or technical specifications provided by the relay manufacturer. The datasheet contains crucial information about the relay’s operating parameters, including its voltage rating, coil resistance, and other performance characteristics.

In summary, it’s generally not advisable to run a 12V relay on a 35V power supply without implementing additional protective measures. If the power supply voltage cannot be adjusted, consider using a relay with a higher voltage rating that is compatible with the supplied voltage. Always refer to the relay’s datasheet and follow manufacturer guidelines to ensure safe and reliable operation.

Recent Updates