Initial set up of automatic voltage regulator

  1. Begin with frequency at minimum setting. Set voltage and stability to mid position. On the Mark I and X regulators, the dip switches 1, 2, and 3 should be down and 4 up.
  2. With the generator running under NO LOAD, set the voltage pot to obtain the correct setting. Then set the stab pot to make the voltage stabilize. Use the minimum amount of stability that is necessary. It may be necessary to readjust the voltage after setting the stability to obtain the correct values.
  3. With the generator running under NO LOAD, decrease the speed of the generator by 10%. Rotate the frequency pot to the point that the voltage begins to drop and stop. This is the correct adjustment for the low speed protection. If set correctly, the generator voltage will continue to decrease as the speed decreases from this point. The voltage should remain constant from the nominal speed to the 10% reduction in speed. Below this point, the voltage should drop as the speed decreases.
  4. Set the amp pot to 75% of rotation. This is over excitation protection for the generator rotor.
  5. On the Mark I and X, the slope pot is bypassed as long as the #4 dip switch is up.

VOLTAGE:This pot adjusts the output voltage of the generator. It allows a wide range of voltage adjustment. To obtain finer voltage adjustment, or to be able to remotely make the adjustment, insert an external potentiometer at terminals P and Q on the voltage regulator. The pot should be rated at 500mW and should have at least 100kOhm of resistance. This will allow a +/- 5% voltage setting. More resistance will allow more adjustment.

FREQUENCY: This is the low speed protection setting for the excitation current. Under generator operation, the excitation current will increase when the rpm’s of the generator decreases. This is to keep the voltage at the nominal level. To keep the AVR from supplying too much current to the rotor (which will ultimately burn up the generator), the frequency pot must be correctly set. As the set up explains above, the AVR will decrease the current to the excitation system when the speed drops below 10 % of nominal. The jumper wire that is on the terminals 60 and HZ is in place for the low speed protection to operate properly at 50 HZ. When this jumper is removed, the AVR low speed protection works properly at 60 HZ. However, the frequency pot must be set correctly in either circumstance.

STABILILTY: The stab pot is for making the output voltage setting remain constant. As the stab pot is rotated, the voltage will become more stable. However, this setting has a downfall. The more stability that is used, the longer the recovery time is from a voltage drop. This is why the minimum amount of stability should be used. When a load is suddenly applied to a generator, the voltage will drop and this takes a small amount of time to recover. This time will increase as the stability setting is increased. The 1, 2, and 3 dip switches on the Mark I and X AVR are extra stability settings. They each have a different stability value. If the stab pot is not enough to stabilize the voltage, these switches can be turn on one at a time, in any order, or any combination of the three. These will work in series with the stab pot to obtain correct voltage stability.

AMP:This pot is for over excitation protection of the rotor. This is the setting that will be the maximum amount of current allowed to go to the exciter field, taking all other settings into consideration. The factory suggests the 75% setting. This will not affect the voltage drop, stability, or any other function of the generator.

SLOPE: This pot is normally bypassed when the #4 dip switch is up. This is the normal operating position. If needed, the slope pot allows manual control of how much excitation current is used to help the generator recover from a voltage drop when placed under load (generator decreasing in rpm). More excitation current will cause the generator to recover voltage lost from a decrease in speed faster, but the more current that is used will decrease the life of the generator. Remember that too much excitation current causes rotor damage and ultimate generator failure.

OVERVOLTAGE: This pot is the adjustment setting for the output voltage terminals on the AVR. It controls the amount of voltage that is available at out 1 and out 2 for connecting external devices such as relays or lights for a control panel. Does not affect generator performance.