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ge:diesel-generators:start [2013/01/24 13:03] – [Diesel Generators] Alan Sheage:diesel-generators [2013/01/24 16:40] – ge:diesel-generators:start renamed to ge:diesel-generators Alan Shea
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 DC systems have current flowing in a single constant direction with typically steady voltages and are commonly seen in battery powered systems. AC systems have current directional flow alternating, typically many times a second; the voltage also varies in a sine wave pattern, from zero to a positive peak then back down to zero and down to a negative peak then rising back to zero in each cycle. Since the voltage is constantly varying, the voltage is expressed as //RMS// (root mean square). RMS is a mathematical calculation of the sine wave voltage to give the DC voltage that would provide equivalent power. Peak RMS voltages are higher than the RMS value by a factor of 1.414 (the square root of 2). So a 120 volt AC system will have peak voltages of about 170 volts, and 220 volt AC system peak voltages of about 308 volts. DC systems have current flowing in a single constant direction with typically steady voltages and are commonly seen in battery powered systems. AC systems have current directional flow alternating, typically many times a second; the voltage also varies in a sine wave pattern, from zero to a positive peak then back down to zero and down to a negative peak then rising back to zero in each cycle. Since the voltage is constantly varying, the voltage is expressed as //RMS// (root mean square). RMS is a mathematical calculation of the sine wave voltage to give the DC voltage that would provide equivalent power. Peak RMS voltages are higher than the RMS value by a factor of 1.414 (the square root of 2). So a 120 volt AC system will have peak voltages of about 170 volts, and 220 volt AC system peak voltages of about 308 volts.
  
-=====Ratings=====+====Ratings=====
 Generators are typically sold by kW capacity with a kVA rating also provided. Gensets are typically rated for Prime or continuous duty rating and at higher rating for Standby or limited run hours. It is wise to by the unit based on the lower kVA Prime or continuous duty rating if it is to take to place of utility power and run all day or over 12-14 hours a day. Generators are typically sold by kW capacity with a kVA rating also provided. Gensets are typically rated for Prime or continuous duty rating and at higher rating for Standby or limited run hours. It is wise to by the unit based on the lower kVA Prime or continuous duty rating if it is to take to place of utility power and run all day or over 12-14 hours a day.
  
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 At cooler temperatures and for short periods the genset can deliver slightly above its rating. This allows for motor starting loads and brief load transitions. How well it will perform during this overload varies with the ambient air temperature, amount of overload and duration. You are at the edge or outside the envelope here so anything you get be grateful for. Planning under normal conditions not to exceed 80% of the engines rating is wise. At cooler temperatures and for short periods the genset can deliver slightly above its rating. This allows for motor starting loads and brief load transitions. How well it will perform during this overload varies with the ambient air temperature, amount of overload and duration. You are at the edge or outside the envelope here so anything you get be grateful for. Planning under normal conditions not to exceed 80% of the engines rating is wise.
  
 +See [[Prime vs Standby]]. 
 ====Frequency==== ====Frequency====
 The frequency of the output voltage is directly related to the engine speed. Thus with typical 4 pole armatures, a 50Hz machine will run at 1500 RPM and a 60 Hz machine will run at 1800 RPM. Engine speed is controlled by the governor. If you are having frequency and engine speed problems that is where to look, not the alternator or voltage regulator. The frequency of the output voltage is directly related to the engine speed. Thus with typical 4 pole armatures, a 50Hz machine will run at 1500 RPM and a 60 Hz machine will run at 1800 RPM. Engine speed is controlled by the governor. If you are having frequency and engine speed problems that is where to look, not the alternator or voltage regulator.
ge/diesel-generators.txt · Last modified: 2018/05/28 22:29 by 127.0.0.1

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