With years of experience in providing generators, we often get asked a number of questions and queries. So we’ve put together the most frequently asked questions, to help and assist with any answers you may require.
There are many different types of generators to choose from, how do I decide which product to choose?
In this day and age, there’s many different types of generators out on the market, with Bellwood Rewinds you can buy in confidence as our products are of only the best quality.
What size generator do I require?
All electrical products have data plates which include information about their power usage. Electrical items have their wattage listed and include all the power required to run them. So if you check the amount of wattage you’re going to be powering, you can choose a motor which meets this.
If you’re unsure as to the power usage a product has, it’s a good idea to contact the relevant manufacturers sales or technical department, you can quote the model number and request the start up wattage and running wattage of the item. Once you have received this information you’ll be able to determine the accurate size of the generator you require.
Do I need a generator that has a long run fuel tank?
Generators are available in either standard or long run versions, standard tanks last for 2-4 hours and most long run generators can run through the night, should you be looking to purchase a generator for back up (power cuts) then we recommend a long run tank machine.
Do I need to run a computer off my generator?
Running home computers from standard generators is not advisable, you’ll need a generator that utilises AVR (Automatic Voltage Regulation). These type of generators will provide a more stable electricity than the mains, if the generators run out of fuel, the engine is likely to surge. Avoid this affecting electronic equipment by using a Uninterruptible Power Supply, these are typically sold for use with computers so that data is not lost in the event of a power cut.
I’ve bought a generator, can I use a personal power breaker?
Generators are configured differently to mains supplies, it’s recommended to use a personal power breaker from the mains for the majority of cases. It’s not necessary to use one with a generator. Personal power breakers are designed to operate from the mains. If one is to be used with a generator, then it’s necessary to modify the generator so that it is configured in the same way as the mains. This is a simple change for a qualified electrician and involves adding a link wire.
What is the difference between kw and kva?
There are 3 types of electrics…
Real power is measured in Watts (W) and is power drawn by a resistive load, for example a heater element in a kettle and a power factor of 1.
Reactive power is measured in Volt Amperes reactive (var’s), this power is drawn by a reactive load (a load with a winding around a core) an electro-magnet has a power factor of 0.
Apparent power is measured in Volt Amperes and has a combination of resistive elements. The combination for the elements means that both real power and reactive power are drawn together.
The proportion of real power to reactive power is defined as the power factor. The vast majority of single-phase loads have power factors approaching 1, therefore a single-phase generator power ratings are taken at power factor =1, and in Watts or kilo Watts. Three phase loads tend to have lower power factors approaching 0.8, therefore, three phase generator power ratings are taken at power factor =0.8 and are in va or kva.
There is a relationship between real power, reactive power, apparent power and power factor.
Can I operate sensitive equipment from a generator?
The output from the generator isn’t as stable as that from the mains supply, the speed of engine driving there alternator is controlled by a simply mechanical governor, consequently the speed will drop as the load increases. The frequency of the output voltage is directly dependent on the engine speed, meaning the frequency of the output varies with load. The output voltage will vary with load and with temperature. Output voltage of most standard generators will remain within 230v +/-105 from no load up to the rated current quoted on the dataplate. This will be the guaranteed range of voltage supplied from the mains utilities.
The frequency of the output voltage will vary typically from 53hz at no load to 49hz at rated load current, whereas mains supply is unlikely to vary by more than 0.1hz. Most electronic equipment is designed to cope with these fluctuations and will run normally, it’s always recommended to ask the equipment supplier whether their equipment supplier whether their equipment is suitable to be operated from a portable generator.
As a generator rungs out of fuel the engine is likely to surge, avoid this affecting electronic equipment with an Uninterruptible Power Supply, these are typically sold for use with computers so that data is not lost in the event of power cut.