When your AC motor isn’t functioning as expected, it’s important to take steps to identify the problem before deciding to replace it. Here are three methods you can use to troubleshoot your AC motor with a circuit tester.
AC motors are straightforward to operate. Once connected to power, they run at a consistent speed and stop when the power is disconnected. Often, when an AC motor malfunctions, it’s due to a power or wiring issue. The key is isolating potential problems.
What is a Circuit Tester?
A circuit tester, also known as a multimeter or multitester, is an electronic tool that combines the functions of a voltage meter, ohmmeter, and ammeter. It allows you to measure voltage, resistance, and current in a circuit.
First, Check the Basic Wiring
When your motor isn’t working despite being connected to a power source, the first step is to inspect the wiring and ensure that essential components are in good shape. Since various components in the power supply circuit, such as relays, switches, or controllers, can impact motor operation, it’s best to start with the simplest circuit possible. This involves connecting the AC motor and capacitor directly to the AC power supply. If the motor operates correctly, you can reintroduce components one by one to determine their functionality.
Tip: Many AC motor problems result from faulty components or incorrect wiring. To simplify troubleshooting, start by checking the most basic circuit. After confirming its functionality, test each individual component as it’s reintroduced into the circuit.
Three Things to Test with a Circuit Tester
Here are three ways to help diagnose an AC motor problem:
1. Compare the applied voltage with the capacitor’s terminal voltage.
2. Verify if electricity is being conducted through the extension cable.
3. Verify motor winding resistance.
Let’s walk through each test and what it reveals.
Test 1: Compare Applied Voltage with Capacitor Terminal Voltage
If everything is connected correctly, the capacitor terminal voltage should be approximately 1.7 times the power supply voltage. This ensures the motor is receiving the appropriate voltage.
To conduct this test, use Circuit Tester A as shown in the diagram. Connect the red probe to the exposed part of the red wire and the black probe to the exposed part of the black wire, ensuring good contact. Set the circuit tester to AC voltage measurement mode before beginning. If the connections are correct, Circuit Tester A will display the power supply voltage. For simplicity, we used a 100 VAC motor in the example, so the tester should display 100 V.
Next, use Circuit Tester B as shown in the diagram. Connect the red probe to the exposed part of the red wire and the black probe to the exposed part of the white wire. If the connections are correct, the tester will show a value about 1.7 times the power supply voltage. In this case, the tester should read 170 V.
Compare the two readings. The capacitor terminal voltage (red/white) should be approximately 1.7 times the power supply voltage (black/red).
What If I Don’t Have a Circuit Tester/Multimeter?
To check if a capacitor is present in the circuit, manually rotate the motor shaft while the power is on. If no capacitor is connected, the motor will turn in the direction you apply force.
Review: [Insert relevant call-to-action here]
Test 2: Verify Electricity Conducted Through the Cable
A break in the motor’s circuit with its power supply can prevent it from working properly. Testing continuity can confirm if the circuit is open or closed.
Do this with the power off. Use Circuit Tester C and D as shown in the diagram to test the continuity of the cables from the motor to the power supply. Connect the black and red probes from the circuit tester to the exposed connection points closest to the motor and the power supply. If there’s no break in the circuit, the tester will beep.
Test 3: Verify Motor Winding Resistance
Measuring the motor’s winding resistance and comparing it to the original design values can confirm the motor’s electrical condition.
Before measuring, remove all additional components, such as extension cables and capacitors, from the circuit. Switch the circuit tester to resistance value measurement mode. Use Circuit Tester E and F in the diagram to connect to the exposed parts of the lead wires directly from the motor.
We’re using a 100 V motor as an example (model: 2IK6A-JA). For this motor, both Circuit Tester E and F should read 170 ohms. If the winding is broken, the tester will show a value over several thousand ohms. If there’s an internal short circuit, the reading will be less than 170 ohms. For other motors, consult the manufacturer for the designed values. There’s typically a tolerance of about ±10% for winding resistance.
What Do I Do If My Motor Doesn’t Pass These Tests?
When a motor fails to work, it could be due to a bad motor or a faulty component causing the motor to appear nonfunctional. Examples include defective switches, relays, cables, or incorrect voltage. These tests provide valuable clues on what needs fixing.
Examples:
- If the motor doesn’t pass Test 1, check/replace the capacitor or wiring.
- If the motor doesn’t pass Test 2, check/replace the cable or connector.
- If the motor doesn’t pass Test 3, replace the motor.
Mechanical issues, such as a damaged ball bearing due to excessive radial or axial loads, can also stop a motor from operating. To test this, remove the motor and gearhead and attempt to rotate the shaft in both directions. If the motor shaft or gearhead shaft feels locked up without any load, something may be wrong. Abnormal noise or friction while turning the shaft might indicate damage or misalignment. The best course of action would be to replace the motor and/or gearhead.
Becoming a better motor troubleshooter involves understanding the product better. Explore these related posts to enhance your knowledge of AC motors (or speak with our technical support engineers).
Related Posts:
- Show & Tell: AC Induction Motors
- Show & Tell: AC Reversible Motors & AC Electromagnetic Brake Motors
- How-To Videos: Wiring Different AC Motors
- White Papers: AC Motor Technology
Contact Our Experts
If you encounter further issues or need assistance, don’t hesitate to reach out to our team of experts for guidance.
1.5-1.7 ton Mini Excavator, the overall use of engineering additive track, wear-resistant and stable;
This kind of small excavator has beautiful appearance, full power, three-cylinder engine and stable performance;
The front end can be equipped with a side swing function, flexible operation in a small space, large counterweight, and the excavator does not tilt its head when the excavator, and the digging force is increased.
We are a real manufacturer, looking for agents all over the world
1.7 Ton Micro Excavator,1.7 Ton Mini Excavator New,1.7 Ton Small Digger New,1.7 Ton Mini Digger
Shandong Davoo Machinery Co., Ltd. , https://www.sddigger.com