Twenty-four-volt transformers are typically used as control devices. These low-voltage devices are used as step-down transformer in which a higher voltage, generally 120 VAC, is made into a lower working voltage for switches or relays. This basic procedure is an efficient way to test a low-voltage transformer for proper operation.
Things You'll Need
Remove all electrical power from the electrical appliance or device. Never perform this test with any outside source of electrical power going to the device. Use the screwdriver to remove any electrical covers that may conceal the transformer. This may entail using a manufacturer's set of instructions to correctly access this location.
Understand that there are two sides to the 24-volt transformer. The high side is the line-voltage of the transformer. This is the electrical connection to the feeding voltage, generally a 120-VAC power. The secondary side, or low-voltage, side is the power that is transformed to 24 volts. There is no direct electrical connection between the high side and the low side areas of a transformer used for a 24-volt application.
Switch the volt ohmmeter to "ohms" and insert the test leads into the meter. The red lead goes into the slot that reads "ohms" and the black lead goes into the common opening. Touch the two leads together and the ohmmeter should be reading "zero ohms," or a closed circuit.
Place the leads of the ohmmeter to the leads on the high side of the transformer. The meter should be identifying a resistance reading. This reading will vary with the type of transformer used in the circuit. If the meter indicates an open circuit or infinite resistance, the transformer is bad on the high side and must be replaced.
Follow the same procedure from Step 4 on the low side connections. The meter should give the same resistance reading, results in ohms for the low side. If the meter shows an infinite reading or wide open, the low side is broken internally and the transformer must be replaced.
Tips & Warnings
- If the transformer tests are positive (i.e., a good reading), check for blown fuses in the circuitry. The electrical schematic for the circuit should be consulted. Follow all local and state electrical codes when servicing or replacing any electrical device.
- Oil Burners; Audel Press; Edwin M. Field; 1978
- Testing Transformers
How to Check a Transformer
How to Test a 24 Volt Transformer. Twenty-four-volt transformers are typically used as control devices.
How to Find Problems in a 24-Volt Electrical System
The 24 volt transformer is used in a myriad of applications from neon signs to audio/visual equipment. ... How to Test a...
How to Troubleshoot Electrical Transformers
For this tutorial we will practice using a 110-volt step-down transformer with a 18-volt ... Power Transformer Troubleshooting. ... How to Hook...
How to Test a 24 Volt Relay
How to Test a 24 Volt Relay. Relays are electromechanical devices, meaning they have moving parts and are susceptible to failure. ......
How to Wire a 24V Transformer
How to Test a 24V Furnace Transformer. While complicated furnace repairs should be handled by a professional, ...
How to Wire a Furnace Transformer
How to Wire a Furnace Transformer. A transformer links a furnace's high-voltage and low-voltage circuits together. ... A 24 volt transformer, ...
How to Hook Up a 24 Volt Transformer to a 110 Volt Outlet
How to Wire a 120 Volt to 24 Volt Transformer. A transformer is a device that changes one voltage level in an...