Generator Not Generating Power? Fixes Here
Having a generator fail to produce power when you need it most can be incredibly frustrating. Whether you rely on a generator for backup power during outages or use one at a job site, any loss of power can bring work to a grinding halt.
Fortunately, many common generator issues that prevent power production are easy to identify and repair yourself. With some basic troubleshooting, you can often have your unit up and running again in no time.
Check for Loss of Residual Magnetism
The most common reason for generators not producing power is a loss of residual magnetism. All generators rely on magnetism to produce voltage. Over time or after connecting a load that drains the residual magnetism faster than it can rebuild, the magnetic field can collapse.
Check for a loss of residual magnetism by trying to restart the generator. If you get a reading between 50-70 volts per phase at the output without any major increase after a few minutes, the automatic voltage regulator (AVR) may be bad. If the voltage stays between 0-5 volts per phase, it is likely a loss of residual magnetism.
Methods to Restore Residual Magnetism
The easiest way to regain residual magnetism is by briefly connecting a battery. Hook the positive lead to the positive brush and negative lead to ground for 5-10 seconds. This will help jumpstart the magnetic field. Disconnect before trying to start the generator.
Spinning the rotor with an electric drill for 30+ seconds can also help amplify any existing residual magnetism to the point where the generator can self-excite again. Go slowly to avoid damage.
Finally, check that your generator runs a load nearly every time it operates. Allowing the unit to run unloaded for extended periods drains residual magnetism over time.
Fuel System Problems
Like any engine, generators rely on proper fuel supply for operation. Issues like clogged fuel lines, faulty fuel pumps, or dirty filters can all prevent startup and power production.
How to Check the Fuel System
Start by confirming adequate fuel levels. Overflowing the tank or running too low can both cause flow problems. The fuel filter may also need replacement if working with old or dirty gas.
Verify fuel is actually pumping through the line into the carburetor. Detach the line to check flow quality. If flow seems low, check for crimps in fuel lines or failures in the fuel pump preventing proper feed.
Finally, disconnect and clean out the carburetor bowl if debris have clogged pathways through. Properly reattach the carb before attempting to restart.
Ignition System Troubleshooting
Without good spark, no engine will run properly. Use the following process to step through potential ignition problems:
- Check that the spark plug is properly connected. Detach and reattach to ensure a tight connection.
- Visually inspect the spark plug. Look for excess debris buildup or worn out components needing replacement.
- Test for proper spark by disconnecting the wire and holding it near metal while cranking the engine. You should see a strong blue spark.
- Check for broken ignition system wires causing connectivity issues.
- Ensure circuit breakers have not tripped, disrupting flow to components.
By methodically reviewing each part of the system, you can identify and correct any defects preventing spark generation.
Generator Engine Problems
If fuel and ignition systems check out, underlying engine issues may be the culprit. Here are some common generator engine problems and remedies:
Oil Related Shutdowns
Many generators have low oil auto-shutdowns to prevent engine damage. Check the oil level first before further troubleshooting. Top up if running low. Oil changes may also help if operating with old or dirty oil.
Replacing Air and Fuel Filters
Dirty air and fuel filters slowly choke flow over time, starving the engine of needed inputs. Swap out filters per the manufacturer's recommendations or if visibly dirty.
Choking
Fuel flooding from excessive choking when trying to start the stalled generator is another issue. Check that the choke is properly operating. Manuel chokes should only be closed when cold starting.
Alternator Problems
A bad alternator directly causes power production problems. Check output voltages and currents to confirm alternator operation. Replace if voltages are zero or very low relative to expectations.
By addressing each major generator system - fuel supply, ignition, engine operation, and electrical output - you can properly diagnose why your generator fails to produce power and correct the underlying issue.
While troubleshooting the main systems will solve most power loss issues, there are some less common causes worth mentioning:
Poor Electrical Connections
Intermittent or nonexistent power despite proper generator operation may come down to loose connector issues. Inspect all ports and terminals for dirt, debris, and wear. Clean contacts should have a bright, shiny look indicating good electrical flow.
Check screw terminals are tight and wires fully inserted into ports. Wiggling wires while operating can detect loose fittings. Any identified poor connections should be tightened, cleaned, or replaced.
Excitation Circuit Wiring Problems
The excitation circuit provides critical power to create magnetism for electricity generation. Shorts or open breaks in the wiring disrupts flow, potentially causing power loss. Thoroughly inspect the wiring for damage or incorrect connections.
Measure winding resistances with an ohmmeter to check for partial shorts or opens. Repair any identified wiring faults before attempting to restart.
Tripped Breakers
Both internal and external breakers may trip due to power spikes, shorts, or overloads. The generator may appear dead until these breakers are reset. When troubleshooting, check both breaker panels for tripped handles before assuming other issues.
Determining what caused the breaker trip is also wise to prevent immediate re-trips upon reset. Common causes include faulty power cords to connected equipment, rainwater induced shorts, or damage to the generator windings.
In some cases, generators still fail to produce power despite basic troubleshooting. More advanced diagnostics and repairs may provide the answer.
Thermography
An infrared thermography camera can identify hot spots that indicate problems areas. For example, a hot connection may point to loose wiring decreasing conductivity. An experienced technician can analyze imagery to rapidly narrow down issues.
Check Windings
Cracked or grounded out windings disrupt power generation. Use a 500 volt ohmmeter to measure the ground insulation of generator windings for faults. Replace or re-insulate any problem windings found.
Replace Brushes
Over time, brushes wear down through friction eventually failing to conduct. Inspect and replace brushes if excessively worn. Take care to match new brushes to the original specifications.
Some issues come down to faulty parts needing replacement by a skilled technician. Common culprits are worn AVRs, bad capacitors, and defective breakers. Follow proper disassembly, testing, and reassembly methods when replacing these generator components.
While generators may seem mysterious when dead, methodical troubleshooting and repair guided by an experienced electrician can typically get them humming again. Pay attention to fuel, ignition, engine operation, and electrical connectivity issues to rapidly isolate why your generator fails at producing power.
And when preventative maintenance does not work, advanced tools like infrared imaging and winding insulation testing combined with component replacements can help restore generator functionality. Knowing the proper systematic checks and repairs will save hours of headache when your generator goes down.