Control-circuit troubleshooting
Equipment that will not start, will not stop, starts on its own, or stops for no visible reason. Traced through the control circuit device by device rather than by replacing the most expensive part first.
Control circuits, relay logic, starters, interlocks and control panels — repaired, modified, rebuilt and traced out when nobody has the drawings. The wiring that tells equipment when to run is where a surprising number of faults live.
Light-industrial and commercial control circuits on shop equipment, pumps, wash systems, conveyors, fans, heating and process machinery.
Equipment that will not start, will not stop, starts on its own, or stops for no visible reason. Traced through the control circuit device by device rather than by replacing the most expensive part first.
Control relays, timing relays, latching circuits, sequencing and permissives. Failed coils, welded or pitted contacts, and relays that have been jumpered out at some point and never put back.
Push buttons, selector switches, pilot lights, e-stops and remote stations. Contact blocks that have failed open, devices full of dust or moisture, and stations that were never labelled.
Door and guard interlocks, e-stop circuits, limit switches and permissives that keep equipment from running when it should not. These get repaired to work, not bypassed.
Float switches, pressure and vacuum switches, thermostats and temperature controls, proximity and limit switches, photo-eyes and flow switches. Often the actual cause behind an intermittent shutdown.
Panel repairs and modifications, replacing obsolete relays and controls, adding circuits, tidying and re-terminating wiring that has been added to over the years, and replacing failed control transformers.
Small control panels built or rebuilt for a specific machine or process — enclosure, starters, overloads, relays, control transformer, terminals and labelling, wired to suit the equipment.
Equipment with no drawings, panels modified by several people over many years, and machines moved in from another site. Tracing out what is actually there is often the deliverable.
Terminal and device labelling, panel schedules, circuit identification and a marked-up record of how the circuit actually works — so the next fault takes an hour instead of a day.
When a machine stops, attention goes to the machine. But the motor, the drive and the mechanical side are only part of the picture — the control circuit decides whether any of it is allowed to run. A machine that is dead because a $12 pressure switch has failed open looks identical, from the operator’s side, to a machine that is dead because the motor is burnt out.
The practical difference is where you start. Confirming control voltage, then working through the permissives in the order the circuit uses them, usually finds the break faster than testing the load side first. It also avoids the expensive version of this problem: a new motor or drive installed against a control fault that is still there.
A lot of equipment in Central Alberta shops is older than the people running it, and the control components are no longer made. That is usually workable — a modern relay, timer or control device can be adapted to do the same job, provided the circuit is understood first. Where a direct replacement exists it gets used; where it does not, the substitute gets documented so the next person is not guessing.
Interlocks, guards and e-stops exist because somebody was hurt once. If a safety device is faulty, it gets repaired or replaced — not jumpered to get through the shift. Where a machine genuinely has to run before a part arrives, any temporary arrangement has to be safe, and if it cannot be, you will be told so directly.
Yes — that is common, and tracing the circuit is part of the job. Expect it to add time on the first visit, and expect to come away with a marked-up record of how it actually works, which makes every future call shorter.
Small panels for a specific machine or process, yes — enclosure, starters, overloads, relays, control transformer, terminals and labelling. Large engineered panel builds with formal drawing packages are outside what an owner-operated shop takes on.
Relay logic, hardwired control circuits, drives and the electrical side of PLC-controlled equipment — wiring, I/O, sensors, field devices and troubleshooting — yes. PLC programming and software development is a different trade; if that is what the job needs, you will be told so rather than have it attempted.
That is the usual description. It is worth noting exactly what the machine was doing each time and whether there is any pattern by time of day, load or material. Intermittent control faults are often a device that fails when it heats up, a connection that opens under vibration, or a safety device doing its job on a condition nobody has noticed yet.
Call for service, or send photos of the panel and a description of what the machine is doing.