In North America, the largest market for generator sets is for standby power. In residential, commercial and industrial uses, standby generator sets provide a reliable AC power supply to carry the home, institution, public facility or business through a utilities power outage.
Because electrical utilities are so reliable, standby power systems tend to use higher engine and generator output ratings. This is because over the entire life of the generator set it may only run a few hundred hours. Therefore there are restrictions on the usage of the generator set. Typically the number of operating hours per year must be less than 200. There is no overload capability.
Standby generators often interact with other building systems such as fire suppression. They are usually started and stopped automatically through a control system that monitors the utility power feed.
Emergency Electrical Power Supply
This term is used by building or electrical codes for standby power systems for applications such as hospitals, nursing/care homes, and residential buildings with fire pumps and elevators. These systems typically must provide power within 10 seconds to all life safety systems, including emergency lighting, exit signs, fire alarms, and so on. Unlike other standby power systems, emergency power systems in Canada (and the US) must be on a separate conduit system with separate panels and transfer switches.
The Frontier Power—Kohler Advantages
Here are two reasons why you want to talk to us about your standby generator needs:
- Most of Kohler’s industrial generators are powered by either a John Deere or Mitsubishi engine. We are very familiar with these engines given that we are exclusive distributors of John Deere and Mitsubishi engines in Western Canada.
- Kohler selects from a wide selection of engines, including John Deere and Mitsubishi, to power their generators. Not being tied to one engine supplier allows us to deliver a generator with the best load response for your application.
Checklist of Things to Consider
Common single phase voltages in North America are 120/240. These voltages are often supplied by generator sets as they are frequently used in household type loads.
Common three phase voltages found in North America are 120/208, 277/480 and 347/600. (Measured – line-to-neutral/line-to-line).
Most of North America is 60 Hz or 60 cycles per second for AC power supply. It is not uncommon to have European or Asian equipment to power and this is usually 50 Hz. AC supply.
To produce 60 Hz power, engine driven generators will operate at 1800 rpm using a 4-pole generator. Lightweight, portable or residential generators may operate at 3600 rpm with a 2-pole generator. Larger generator sets may run at 1200 rpm (6-pole) or 900 rpm (8-pole) or 720 rpm (10 pole). (50 Hz is similar but 3,000 rpm for 2-pole, 1500 rpm for 4-pole, 1000 rpm for 6-pole etc.)
Residential and most light commercial services are single phase. Larger commercial and industrial services are normally three phase. Although there is no hard and fast rule, generators over about 50 kWe are usually three phase. On larger sets, if the loads are single phase loads, the line-to-neutral power is divided, as equally as possible amongst the phases to balance the loads on the generator’s windings.
In this case, “kilowatts” refers to generator output kilowatts or kWe (sometimes ekW). The actual load on the generator set engine are the kilowatts required to operate the load. This should be carefully sized because the engine cannot be efficient without an adequate load. Too little load may cause diesel engines to “carbon up” with unburned fuel. This leads to sooting of the lubricating oil, wear and eventually, premature engine failure. Conversely, too much load can shorten the life or damage the engine and generator.
kVA is apparent load on the generator. The generator must be sized for the kVA requirement. Typically we use 0.8 as a power factor to estimate kVA. This is a convention and the power factor should be used if it is known. If the power factor is estimated, then the kVA will be the kWe ÷ 0.8 = kVA. (e.g. 100 kWe = 125 kVA where the power factor is 0.8)
What will be the highest and lowest temperatures at which the generator will be expected to function? What will the maximum altitude be? Will it operate in dusty conditions? This will affect the air cleaner and pre-cleaner selection on the engine and may affect the fin spacing on the cooling radiator. Low temperatures will affect start-ability, oil grade and ancillary equipment.
If the generator will be housed in an enclosure you may want to think about the possibility of the enclosure being affected by ice buildup or other weather related concerns. Service access will normally be looked after by the supplier but deserves consideration. Is sound attenuation required?
Controlling the noise level of a standby generator is another factor that needs to be considered given that these generators are usually located in close proximity to residents or workers. Advance planning for sound attenuation includes having sufficient space for a suitable exhaust system and, if required, for an enclosure.
When it comes to emergency, standby and backup power generators, it is hard to beat Kohler.
Have a look at the industrial generators offered by Kohler Power Systems and then give us a call to discuss your customer’s or your requirements.
Industrial Generator Sets (10–3250 kW)
From distributed generation and load management to power quality for mission-critical applications, our Kohler sales specialists have the knowledge and resources to offer complete system solutions. We welcome your requests for quotes, sizing, or questions on application and system design.
Towable Generators (20–500 kW)
Towable generators adapt to your needs, wherever they may be. With features like heavy-duty camlock kits, rugged trailer and housing construction to withstand the elements, and state-of-the-art digital controls, Kohler has quickly become the clear choice in the industry. Choose your application, Kohler has a durable, cost-effective towable power generation solution to meet your needs.
Kohler offers a full line of automatic transfer switches for a basic emergency standby system to a complete multi-generator, multi-utility system.