Most winter outages on the farm start the same way. Freezing rain loads the lines, the wind picks up, and a pole between the substation and the yard gives out. In January, with a full barn and the thermometer near minus thirty, that means frozen waterers, a well that will not pump, and fans that stopped hours before anyone noticed.
Farms that come through a long outage in decent shape usually did the work in the fall, when there was time to read motor nameplates, book an electrician and test the generator on a calm afternoon.
Start With the Loads That Cannot Wait
Begin with a list of what truly has to run. Saskatchewan's livestock emergency guidance names water sources, barn ventilation and heating systems as the priorities. Ventilation in a confinement barn usually tops the list, since problems there can develop in a short time once the fans stop. Water is close behind: the well pump, the pressure system and the heated waterers that keep cattle drinking through a cold snap.
Heat for calving or farrowing areas, milking and milk cooling, and feeding systems such as augers and silo unloaders come next. In the fall, add aeration fans and dryers, since tough or damp canola can spoil rapidly in the bin without air to cool it. The house and shop can usually wait. Call your insurer too. Ontario's generator factsheet notes that many insurers require permanently installed units for some operations, poultry and swine among them.
PTO Units Versus Permanent Standby Generators
Farms generally choose between two types. A standby generator has its own diesel, gasoline or natural gas engine, is usually permanently installed, can start automatically and is often sized for the whole farm. A PTO generator runs off a tractor and is connected and started by hand. PTO units cost about half as much per kilowatt and are often sized for critical equipment only, but someone has to get the tractor hooked up at two in the morning in a blizzard.
Comparing units is easier if you start from a list of farm and PTO generator suppliers and ask each for the continuous rating, surge rating, PTO speed and voltage regulation in writing. With PTO units, the tractor sets the limit. Ontario's guidance calls for 2 brake horsepower per kilowatt, so a 40 kW generator needs a tractor in the 80-horsepower range. Never run a tractor with a 1,000 rpm PTO at half engine speed to drive a 540 rpm generator, because the torque becomes unstable and the tractor may stall or surge.
Check the tachometer too. In provincial tests of 84 PTO generators after the 1998 ice storm, actual PTO speed varied by up to 16 per cent from what tractors showed, and most units had no frequency indicator. An independent meter lets the operator hold output between 60 and 62 hertz.
Sizing Around Motor Starting Loads
Starting load usually decides generator size. The Ontario factsheet recommends assuming a motor needs at least four times its operating watts to start, and as much as twelve times in hard cases such as a silo unloader buried in silage. Its table puts a 5 hp single-phase motor at about 4,550 watts running and 18,200 to start. Heaters and lights draw the same at start-up as running.
Write down running and starting watts from each nameplate and total the running loads. Then set a starting order, and at each step add the next motor's starting watts to the running watts of everything already on. The highest step is your peak. Add 20 per cent for future expansion and round up to the nearest 5 kW. The continuous rating should cover the running total, the surge rating that peak. When the power goes, switch everything off, start the generator, then bring the essential motors on one at a time.
The Connection Belongs to a Licensed Electrician
The tie-in to the farm's wiring is the dangerous part. Without a proper transfer device, generator power can flow out through the main breaker to the pole transformer, which steps it back up to thousands of volts on a line that crews believe is dead. A transfer switch isolates the farm while the generator runs and keeps it from burning out when utility power returns.
That is work for a licensed electrician, with whatever permit your province requires. Ontario's guidance rules out makeshift connections such as clamps or locking pliers, even in an emergency. In Saskatchewan, the provincial utility offers farm-rate customers a replacement power box and meter with a built-in standby switch, and wiring its plug requires an electrical permit. While the electrician is there, get every circuit on every panel clearly labelled.
Fuel, Testing and a Written Outage Plan
Ontario's factsheet recommends at least 72 hours of fuel on hand, and farmers in the 1998 ice storm reported burning an average of 160 litres a day. The fuel tank's electric pump and the tractor's block heater may not work in an outage, so go into winter with tanks full. Switch diesel left over from harvest to winter grade early, because wax crystals that form at the cloud point stay put even after winter fuel is blended in.
Use or replace the fuel in self-contained units every three months and add a stabilizer. Exercise the generator every 90 days, with at least 30 minutes at half load or more, logging voltage, amps and frequency. Post a plan beside the main panel covering which breakers go off first, the order motors come back on, where the PTO shaft and cables are kept, and who to call. Engines run outdoors, or with exhaust piped outside, because of carbon monoxide.
If only one thing gets done before the snow flies, make it the load list with real nameplate numbers. Once the switch is in, pick a mild afternoon and run the barn on generator power for an hour with whoever would do the job at night at the controls. Walk every barn and look at the fans themselves. An Ontario swine specialist has described generators that started while a tripped panel breaker left the barn fans off.
