Emerson MPR25 Low voltage alarm LVA adjustment, Procedure 18 - Low voltage alarm adjustment, Step

Installation and start-up procedures 67

Low voltage alarm (LVA) adjustment

Procedure 18 - Low voltage alarm adjustment

Step Action

1Turn the test potentiometer counterclockwise until the voltage reading on the meter is -47 V. Turn LVA potentiometer R20 (located below the LVA LED) clockwise until the LVA LED lights up, or counterclockwise until it extinguishes.

2Reinstall the LVD unit faceplate removed in Procedure 17.

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LVD/low voltage disconnect / reconnect (LVDR) adjustment

WARNING

Do not switch the NORMAL/BYPASS switch back to the NORMAL position if the LVD/LVDR potentiometers are readjusted and their adjustments are not completely verified. Doing so can cause loss of power to the load.

Note 1 : To ensure that the potentiometer is turned fully counterclockwise, the pot must be turned 20 full turns, or until a click sound, emitted by the pot's clutch, is heard.

Note2 : The effect of the LVDR potentiometer in setting the reconnect voltage level is approximately 1.6 V for each turn for Rel. 2 and 2A, or approximately 0.75 V for Rel. 3 and 3A. The connect/disconnect voltage difference is smaller when the LVDR potentiometer is turned counterclockwise and larger when it is turned clockwise.

Procedure 19 - Low voltage disconnect/reconnect adjustment

Step Action

1Turn the LVD and the LVDR potentiometers fully counterclockwise.

2Turn the LVDR potentiometer four turns clockwise for Release 2 and 2A, or 9 turns for Release 3 and 3A.

3Adjust the voltage measured at the test jacks to -43.5 V with the Test potentiometer.

4Turn the LVD potentiometer clockwise until the LVD LED lights up.

continued

25A Switch Mode Rectifier NT5C06B / C Installation and User Manual