ATS repairs
Generator ATS & Automatic Transfer Switch Repairs
The automatic transfer switch decides when the generator should start and when the building load moves from the mains to the generator, and back. ProService Generator Repairs diagnoses that sequence on standby systems across Gauteng. This is not a guide to opening a live mains board.
- Start signal and transfer
- Contactors and sensing
- No live-board DIY
- Onsite across Gauteng
What the switch is doing
What does a generator ATS do?
On a standby set, the ATS watches the mains. When the supply fails it should call for a start. When the generator is ready it should transfer the load. When the mains returns it should transfer back and allow the generator to stop. A failure at any of those steps looks like “the generator did not come on”, even when the engine itself is fine.
Possible causes include a missing start signal, the controller left in the wrong mode, a mains-sensing fault, a contactor that does not pull in, control wiring, a failed interlock, or a mechanical transfer that does not complete. Those are electrical checks on equipment that can be live. They are not home adjustments.
If the set starts from the panel in manual and only fails when the mains drops, the visit starts at the automatic sequence. If it will not start in manual either, the engine and battery are tested as well.
How the sequence fails
Why is my generator not starting automatically?
A failed transfer is not proof that one contactor is burnt. The step that stopped is identified first.
Generator starts but power does not transfer
The engine is up and the building is still dark. The check moves to the transfer itself: sensing, the contactor and whether the generator is being accepted as a source.
ATS contactor faults
A contactor that will not close, or will not drop back to mains, is tested. It is not bridged out to force a supply onto the board.
Mains-sensing problems
If the switch never sees the mains fail, or never sees it return, the start and the changeback both stay wrong.
ATS and generator controller communication
The controller and the switch have to agree on start, ready and transfer. A display alarm on one and a silent switch on the other are read together.
Commercial ATS repairs
Offices, retail and complexes often depend on this sequence. Access to the switch and a site contact are part of the booking.
Testing automatic operation
The sequence is proved in the order it should happen. A manual start alone does not prove the mains-fail path.
Related Pages
Automatic start, controllers and callouts
Google reviews of ProService Generator Repairs
Google Review
[ProService Generator Repairs] handled the annual load testing and compliance certification for our SDMO plant easily, fixing a faulty automatic transfer switch contactor in the process.
Google Review
They provide extremely quick response times in Joburg North. When our complex ATS board failed, their technicians fixed the wiring in a flash.
Common Questions
Questions about ATS repairs
What is a generator ATS?
It is the automatic transfer switch that starts the standby set and moves the load between mains and generator.
The generator does not start when the power fails. Is that the ATS?
It can be. Possible causes include no start signal, the controller mode, a battery fault, or an alarm that is holding the start off.
The generator starts but the lights stay off. What does that mean?
The engine has started and the load has not transferred. That is a transfer fault, not a no-start.
The mains has come back and the generator is still supplying. Can that be the ATS?
Yes. A failed changeback is a separate step from the original start.
Can I bridge the switch to get power on?
No. Forcing a live board or defeating an interlock is dangerous. The transfer is diagnosed with the supply made safe.
Do you repair the controller as well as the switch?
When the start command or the alarm sits in the controller, that module is part of the same visit. The wider panel wiring is the control-panel page.
Is ATS work part of an installation?
A new changeover can be part of an installation. This page is for a switch that is already there and is not doing its sequence.
What should I send about the transfer switch?
Whether it fails to start, fails to transfer, or fails to return to mains, plus a photo of the controller screen if it shows an alarm.
Still unsure what the fault is? Call or WhatsApp 082 057 4605 for onsite diagnosis.
Service Areas
Onsite visits across Gauteng
Technicians travel to the generator. These are the main Gauteng areas. Suburb pages sit under each region.
What to send before we attend
ProService Generator Repairs confirms an onsite visit from these details. Send what you have. A missing model number does not stop the booking.
- Location
- The suburb or site, so the visit can be booked in the right area.
- Make and model
- The generator brand and model, if they are known.
- kVA
- The size printed on the data plate.
- Fuel type
- Diesel, petrol, LPG, natural gas, or dual-fuel.
- Controller model
- The module name on the panel, when it is visible.
- Fault or alarm
- What the set does, and any text on the screen.
- Photos
- The generator, the data plate, and the controller or alarm. Send these on WhatsApp.
Book a Visit
Describe what the switch did
Say whether the generator started, and whether the building transferred. Do not open the board before the visit.
- Call
- 082 057 4605
- Message us on WhatsApp