The main causes of voltage drop in generator

Some common reasons are :
1). Load applied to generator exceeds capacity, typically would cause machine to slow down, drop frequency and voltage typically cause exhaust black stacking and depending on the overload and protection settings could cause machine to stall.

2). AVR Voltage gain set too low to respond to load being applied.

3). If AVR feedback is from generator bus VT and voltage dips too far, all excitation could be lost and would typically result in an undervoltage and overcurrent trip.

4). Speed control gain set too low to respond to load being applied.

5). Mechanical issue such as failing turbo unable to provide enough air of high enough pressure while taking on load which will cause machine to slow down and in some cases stall on high load application with sufficient reduction in speed voltage will also lower as well as frequency. In this condition you'd probably also see exhaust black stacking.

6). Mechanical issue such as fuel injection clogged or fuel filters clogged causing the machine to be under fuelled to handle load application and may cause machine to slow down, which in turn would drop Hertz and Volts.

7). There's a whole truck load full of other reasons why this could happen.


Leave your comment


9/8/2016 5:14 PM
Thank you sir can any electrical appliances causes low voltage from thecgenerator
9/14/2016 5:03 AM
What is the probable causes that frequency not come up after geneator start.
9/15/2016 9:20 AM
Thanks for the information....
9/18/2016 6:35 AM
Hello All,
I have a three phase connection for my duplex house and hence the ACCL was badly burnt due to sudden surge from Electricity pole. Hence as the cost of the ACCL was high I replaced with a manual Changeover switch. But the output is not controlled and as it is direct from the generator, due to fluctuations in the Generator output My appliances are blowing out one by one due to uneven voltage. Five LED tubelights, microwave was burnt though not switched on, and many other appliances are burning out. Hence I have now disconnected the Generator supply to my house.

Any suggestions how to control Generator output fluctuations as it is directly from generator to my house.

My email Id is

Please provide cost effective solution.
Thanks in advance.
10/3/2016 3:35 PM
Thank you the information.
10/6/2016 6:49 AM
During engine idle operation the generator start hunting l.e hnmmm, hnmm and all the control signal will lost. As result it shortdown on underfrequency. Pls what is the caues for this?
10/15/2016 5:09 AM
Every now an then my genartor the volts will drop an only put ut a lil power I was messing wid plug wigglein it an it started work good but every now an then it will drop any ideas
10/20/2016 7:03 PM
I have a model 40008 champion generator that at times it drop voltage. This could last maybe 5 minutes or as much as several hours. I really don't want to get rid of it as it was my brothers.
10/23/2016 2:10 AM
My generator not giving any output power
11/10/2016 10:40 PM
my 3000 series Shrewsbury is over speeding and I don't now what to du
11/11/2016 5:08 PM
I have an opposite effect on my Volvo 580KVA generator. When almost 40% of the full load is removed from the generator in one step, not only there is no voltage overshoot, but, on the contrary, the votage drops from 380V down to 320V momentarily before recovering.
This is a peculiar beaviour and I have not found a solution. The load removed is a motor (inductive load) running on a soft starter.
Any suggestions?
11/14/2016 11:37 AM
i have a 3 phase stamford generator run by perkins engine. the generator trips on undervoltage while on load. what might be the cause?
11/20/2016 12:49 AM
Dear sir .when we start generator .some time start properly but some time .stop due to .(common voltage/frequency fault alarm )if running 2 o 3 days suddenly stop for this alarm .any solution sir.thanks
11/21/2016 9:21 AM
when a diesel generator developed such fault (voltage drop), which of the causes do we need to start from?
11/21/2016 6:53 PM
Can faulty capacitor cause voltage/current drop
11/21/2016 9:43 PM
Hallow can you assist me with this I have may generator giving the error of over ac volt . What could the problem
12/4/2016 7:21 PM
my diesel generator will shut down while running and will display an alarm abnormal acb trip, what are the causes why my acb will trip while the load at 70 percent?