Step-up and step-down transformers to put a rental generator's output at the voltage your equipment runs on — sized in kVA against the load and quoted from Red Deer with the package it belongs to.
A generator can have every kilowatt the site needs and still be unusable if it delivers 480 V to a switchboard built for 600 V. Canada is unusual here: 347/600 V is the everyday industrial service, while much of the packaged generator market is built around 480 V. Add trailers and tools on 120/208 V and one site can easily want three voltages at once.
A transformer is the piece that reconciles them. It is also the piece most often discovered late — when the set is already on the truck and someone reads the nameplate. Raised at quote time, it is a line on the order. Raised on delivery day, it is a lost shift.
A lot of packaged generators are built for 480 V, while industrial services in Alberta are commonly 347/600 V. Feeding a 600 V switchboard from a 480 V set means stepping up — or choosing a set that already runs at 600 V.
Site trailers, lighting, receptacles and hand tools want 120/208 V or 120/240 V. When the source is a 600 V or 480 V set sized for the heavy equipment, a step-down transformer carries the small stuff off the same supply.
Plenty of sites need both: motors and pumps at 600 V and an office or control building at 120/208 V. One generator and one transformer is often tidier than two generators each running half-loaded.
Before adding one, check whether a different set solves it. Some units in the diesel generator rental and natural gas generator rental fleets are built for 347/600 V and others can be configured for several voltages — the voltage is listed on every unit page.
Transformers aren't listed in the online fleet. They are matched to the voltages and the kVA a job needs and quoted alongside the generator and distribution. Send the source voltage, the load voltage and a load list, and the quote comes back with the transformer specified.
The panels and transfer switches a transformer usually feeds or is fed by, read live from the rental fleet. More on how they are specified on the power distribution rentals page.
Only the load on the far side of the transformer counts towards it. If a 600 V set runs a compressor directly and a 120/208 V transformer serves the trailers, the transformer is sized for the trailers — not for the set.
Divide the running load in kW by the power factor. Without a better figure, 0.8 is the usual planning assumption, so 80 kW of load is about 100 kVA. For three-phase, kVA is also volts × amps × 1.732 ÷ 1,000 if you have currents rather than kilowatts.
Motors draw several times their running current when they start, and site loads tend to grow once power is there. A transformer loaded close to its nameplate all day runs hot; headroom is cheaper than a mid-job swap.
Energising a transformer draws a brief inrush current, and the generator has to ride through it. That is one reason the transformer is sized with the set rather than after it — the two are checked together.
The amperage calculator table gives the current for each kVA and kW rating at standard voltages from 208 V to 4,160 V — a quick way to sanity-check a load list before you send it.
The search terms overlap, but these are different pieces of equipment for different points in the system. Knowing which one you mean shortens the first call.
Air-cooled, with no oil inside. The usual choice at 600 V and below and wherever the transformer sits indoors or near people — a mechanical room, a plant floor, beside a site office. Typically what is meant when a generator package needs its voltage changed.
Normally liquid-filled and sealed in a locked steel cabinet on a pad, built to stand outdoors. Common where a utility's medium-voltage line is stepped down to a building or site service. Oil-filled units bring containment and siting questions with them.
A trailer-mounted unit working at transmission or distribution voltage, used to stand in for a substation during an outage or upgrade. It is utility-side equipment, planned with the utility — a different job from matching a generator to its load.
| Source voltage and phase | What the generator or existing supply delivers — 480 V or 600 V three-phase, for example. |
| Load voltage and phase | What the equipment on the other side expects. The nameplate on the panel or switchgear is the authority. |
| The load itself | A list in kW or amps, with the largest motor called out. That is what decides the kVA. |
| Indoors or out | Whether it sits in a building, a yard or a lease through the winter, and anything about the ground or access. |
| Who connects it | Your electrical contractor, or arranged with the package. Settle it at quote time, not on delivery day. |
| How long | A shutdown weekend, a season or a build that runs past a year all change what makes sense to supply. |
Heavy equipment at 600 V and a trailer compound at 120/208 V, off one source that changes as the build moves through its phases.
Construction site power →A rental set standing in for the utility has to land at the facility's own voltage, through whatever switching the building already has.
Emergency power distribution →At a megawatt and up, the voltage the sets are built for and the voltage the site distributes at are decided together, early.
Megawatt power →Prime power, standby, events and remote camps all draw on the same fleet, distribution and sizing conversation.
Power solutions →Ask. Most transformers go out as part of a package — with the generator and distribution they sit between — because that is when the voltages on both sides are already known. If your site has its own supply and only the conversion is missing, describe it when you call and the desk will tell you what can be supplied.
Transformers are rated in kVA, so start from the load rather than the generator. Total the running load in kW, divide by the power factor (0.8 is a common planning figure) to get kVA, and leave headroom for motor starting and growth. For three-phase, kVA is volts × amps × 1.732 ÷ 1,000. Send the load list and the sizing is done with the rest of the package.
Usually the second, when the fleet has it. Some rental sets are built for 347/600 V and others can be configured for several voltages, so check the voltage on each unit page before assuming a transformer is needed. A transformer earns its place when one set has to serve two voltages, or when the right-sized set for the load is built for a different one.
A dry-type transformer is air-cooled with no oil inside, which is why it is the common choice in buildings and at low voltage. A pad-mount is normally liquid-filled, sealed in a locked steel cabinet on a pad, and built to sit outdoors, often where the utility's medium-voltage supply is stepped down. Which one suits a job depends on the voltages, the location and the site's rules on oil-filled equipment.
This page is about the transformer between a rental generator and the load. Mobile substations work at utility transmission and distribution voltages and are planned with the utility. If that is what your project needs, describe it and you will get a straight answer about whether it is something NexSource can help with.
It is quoted per job with the equipment it serves. The kVA, the voltages, the term and the connection scope all move the number. The sizing conversation costs nothing and the quote comes in writing.
That is enough to specify the transformer, check it against the generator and quote the whole package in writing. NexSource works out of Red Deer and supplies sites across Alberta.
