Tags: MECC ALTE AVR UVR6 for MECC ALTE Alternators,Autotatic voltage regulator UVR6

Description

The UVR6 type voltage regulator is an advanced design electronic regulator that ensures excellent performance of the alternators while they are running and during starting. The regulator is equipped with a complete protection system against operation conditions that could be dangerous for the machine. The UVR6 regulator is suitable for being used with all Mecc Alte alternators and is standard supply for power outputs above or equal to 85 KVA, both three-phase and single phase.

The components of this regulator (see fig. 8) are modern utilising solid-state integrated circuit technology. These components were chosen to guarantee maximum durability and reliability. The entire unit, also made using a hybrid circuit, is inside a box of modest dimensions that has been impregnated with resin to protect against vibrations and ingress of water.

The terminal board is equipped with indications to help connection and avoid errors. Some connection diagrams that are suitable for different configurations are given on the back of the regulator (see fig. 9).

TEST PROCEDURES
Workbench test procedure
-) Prepare the connection diagram as shown in figure 10.

-) Before supplying the circuit with current, take the “VOLT” and “STAB” trimmers to minimum (turn anticlockwise), and the “AMP” and “Hz” trimmers to maximum (turn clockwise). The variac cursor should remain at minimum.
-) Switch on the variac and increase the voltage slowly,making sure that the light switches on and then immediately off.
-) Raise the variac voltage to approximately 200 Vac: the light should not light up.
-) Turn the “VOLT” trimmer slowly clockwise. The lamp should switch on, starting from minimum and going to maximum brightness. Make sure that the green LED
switches on then immediately off again during the brightness intensity changes.
-) Take the “VOLT” trimmer to maximum. The light switches on fully and the green LED remains unlit. Turn the ”AMP” trimmer to minimum (anticlockwise) and wait approximately 20 seconds in these conditions. You should see that the overload protection switches off the lamp and lights the yellow LED. Almost immediately after, the green LED switches on, as does the light but only slightly.
-) Slowly turn the “AMP” trimmer towards maximum.Make sure that the light illuminates with increasing intensity.Leave the “AMP” trimmer at half range.
-) In these conditions, the light should flicker if the “STAB” trimmer is turned slowly clockwise. When the “STAB” trimmer reaches maximum, the flicker turns into intermittent light.
-) Take the “STAB” trimmer back to minimum. The green and yellow LEDs should be lit, and the light should be at medium brightness.
-) Turn the “Hz” trimmer to minimum (anticlockwise).Make sure that the red LED switches on.
NOTE: If the test bench is at 50 Hz and the red LED
does not illuminate, bridge the “Hz” terminals of the terminal board. If the test bench is at 60 Hz and the red LED does not light up, this does not mean that the regulator has problems. The low frequency protection should, instead, be tested in the machine.
-) Short-circuit the remote potentiometer terminals. The light should switch on with greater intensity.If during all the above tests the described behaviour
happens, the regulator being examined is suitable for operation.

Machine test procedure
The regulator should be connected as shown in the relevant diagram in figure 11.

-) Before starting the system, turn the "VOLT" and "STAB" trimmers fully anticlockwise and the "AMP" and "Hz” trimmers fully clockwise.
-) Connect a light between the generator phase and neutral (select the working voltage of the light in relation to the nominal value of the generator phase-neutral voltage).
-) Voltage calibration The output voltage may oscillate when the generator is at no load, at nominal speed and with the “VOLT” voltage trimmer at minimum. If this happens, slowly turn the “VOLT” trimmer clockwise. The generator voltage should rise and stabilise itself. Increase the voltage to the
nominal value. In this situation only the green LED should be lit.
-) Stability calibration To adjust regulator stability, slowly turn the “STAB” trimmer clockwise until the light that was previously connected
between phase and neutral begins flashing slightly.Turn the “STAB” trimmer anticlockwise until the light becomes perfectly stable.
-) Overload protection calibration To adjust the “AMP” overload protection apply a nominal load to the alternator then decrease the speed by 10%
and turn the “AMP” trimmer fully anticlockwise. After a pause of 15-20 seconds, the generator voltage value should decrease and the yellow LED should light up. In these conditions, slowly turn the “AMP” trimmer clockwise until the output voltage value is at 97% of the nominal value – the yellow LED is still lit. When returning to normal speed, the yellow LED should switch off and the generator voltage return to nominal value. If this does not happen, repeat the calibration.
-) Low speed protection calibration If the machine is to work at 60 Hz, make sure that the “60 Hz” terminals of the electronic regulator are bridged. To
adjust the low frequency protection, make the generator run at a speed that is equal to 90% of the nominal one.Slowly turn the “Hz” trimmer in an anticlockwise direction until the generator voltage begins to decrease and at the same time make sure that the red LED lights up. When the speed is increased, the generator voltage should normalise and the red LED should switch off. Take the speed back to the nominal value.If during all the above tests the described behaviour happens, the regulator being examined is suitable for operation.