CNC and manual machines, overhead cranes, plasma tables and welding bays. Machines arrive used, imported or second-hand with a nameplate voltage that does not match the shop, and the control gear inside them is sensitive to power the building has never had tested.
Machine shops, fabrication and welding shops, plate and structural shops, and the mixed shops that do some of each. The electrical reality here is specific: a handful of large, expensive machines, each with its own supply requirement, each with control electronics inside that are far less tolerant of poor power than the motors bolted next to them. Add an overhead crane, chip and dust in the air, coolant on the floor, and a building that has probably been re-laid-out twice as work changed.
The machines themselves are often not new. Used and imported machinery is how most small shops afford capacity, and it arrives with whatever voltage, phase and frequency the previous owner had. A 400 V European machine, a 575 V unit from a plant that had it, or a three-phase machine going into a shop with single-phase service are all common situations, and each has a different answer. Some are solved with a transformer, some with a drive, some only by changing the machine, and the wrong choice is expensive.
Grasse Electric is a licensed, owner-operated contractor working across Central Alberta since 2018. Todd Grasse is a Red Seal Journeyman Electrician, and this is core work here: machine wiring and power, drive and motor control service, machine-shop high-bay LED lighting, and the troubleshooting that happens when a machine starts behaving strangely rather than simply stopping.
What a shop calls about, and what tends to be behind it.
The nameplate says 400 V or 575 V and the shop has 208 V or 600 V. The options are a transformer, a drive, or in some cases replacing the machine’s own supply components. Sorting out feeder, protection, transformer sizing and rotation before start-up is the difference between a machine running and a machine sitting.
Machines that fault randomly, drop out mid-program or reset without a pattern are often being fed poor power rather than failing internally. Supply voltage, imbalance between phases, a weak neutral or ground, and disturbances from other equipment starting all deserve measuring before the machine gets blamed.
Overcurrent and overvoltage faults on machine drives trace back to the supply, the motor, the cable or the load. VFD fault diagnosis checks all four rather than guessing at the drive. Manufacturer experience includes drives such as Schneider Altivar, TECO and Lenze. Grasse Electric is an independent electrical service contractor, not an authorized distributor or factory service provider.
Pendant cables take abuse, festoon systems wear, and contactors in a crane panel fail with use. Hoist, bridge and trolley circuits are all traceable, and lift access means the work can be reached without improvising.
Shadows on a machine table make close work miserable and slow. Machine-shop high-bay LED lighting laid out around the machines rather than on a uniform grid, with task lighting where it is actually needed, is one of the cheapest improvements a shop can make.
Multiple welders on one circuit, undersized receptacles, or a feeder that sags when two machines strike at once. Splitting bays onto properly sized circuits solves what looks like a machine problem.
Flexible conduit cut by chips, boxes full of coolant mist, and devices mounted where swarf lands. The repair is worth doing with the environment in mind, because the same fault returns otherwise.
Motor starters, control circuits and interlocks between the collector and the machines it serves. Confirming control voltage and the starting sequence finds most of these quickly.
Shops outgrow their distribution steadily. Available capacity, feeder sizing and whether a sub-panel makes sense is distribution work that is far better done before the machine shows up on a truck.
The machines and systems that make up a fabrication floor.
Mills, lathes, saws, presses and plasma tables: supply, disconnects, protection, rotation and connection at the machine.
Spindle and axis drives, starters, contactors and overloads, including replacement of obsolete units with current equivalents.
Crane feeds, festoon and conductor bar power, pendant and control circuits, hoist and trolley wiring.
Step-up and step-down arrangements for machines that do not match the shop supply, sized and protected for the load.
Welding receptacles and bay circuits, plasma and cutting equipment supply, and drops positioned around the work.
High-bay LED over machines, task lighting at the work, and wiring for dust collection and fume extraction.
For a new machine, the useful conversation happens before it arrives. The nameplate, the full-load current, the phase and voltage, and whether the machine has its own transformer inside determine everything downstream: feeder size, disconnect, protection, and whether the shop has the capacity at all. A photograph of the nameplate sent by text answers most of those questions in a few minutes, and it is far cheaper than finding out after delivery.
For faults, measurement comes before replacement. Machine control electronics behave oddly when the power feeding them is not clean, and the failure looks like a machine problem until somebody checks voltage under load, phase balance, and the condition of the ground and bonding. Where a machine is faulting intermittently, testing sometimes has to happen while it is cutting, because the fault will not show up on an idle machine.
Work in a machine shop is planned around production. Machine power, lighting and distribution changes get scheduled into a window — after hours, a quiet day, or while a machine is down for service anyway. After-hours attendance is available at an additional charge, confirmed by phone. This is one electrician with service vehicles, a trailer and lift access, which fits machine power, crane and drive work, lighting and shop projects. PLC software programming is outside the scope; field wiring, controls hardware, drive setup and device work are not.
Practical note: when a machine trips on an overvoltage fault during deceleration, the drive is doing exactly what it is designed to do. The energy has to go somewhere, and that usually means a braking resistor, a longer decel time, or a drive configured for the duty. Replacing the drive without addressing that will produce the same fault on the new one.
Usually yes, and usually with a transformer sized for the machine’s full-load current, protected on both sides. Some machines are better handled with a drive, and a few have internal components that make conversion impractical. The answer depends on the nameplate and what is inside the machine’s own cabinet, so send a photo of the nameplate and the internal supply section before committing to a plan.
It may be either, which is why measurement comes first. Supply voltage under load, imbalance between phases, ground and bonding condition, and what else in the shop starts at the moment of the fault all get checked. If the supply tests clean, that is useful information too, because it points the machine builder’s service side at the right place instead of at the building.
No. PLC and CNC software programming is outside the scope here. Drive parameter setup for the motor and load, control wiring, starters, sensors and machine power are all in scope, and that covers the majority of what stops a machine.
The electrical side — feeds, conductor bar and festoon power, pendant and control circuits, contactors and hoist motor wiring. Structural inspection, rigging certification and mechanical crane servicing are for a crane specialist, and any required periodic inspection stays with them.
Rarely. A current-generation drive can usually be fitted to the existing motor and load, with changes at the control terminals and a re-check of the start, stop and interlock logic. What matters is matching the drive to the motor and the duty rather than to the old part number.
Yes, in most shops. High-bay LED work can be staged section by section with lift access, so machines keep running while the lighting over the next bay gets changed.
Send a photo of the nameplate and we can tell you what it needs.
