Generac 91401256S / Bsc 556 — Voltage Regulator Adjustment
Adjustments
For the Generac 91401256S / Bsc 556, from the Generac service manual.
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Before you start
- Adjust voltage regulator only when no-load AC frequency is correct.
Procedure
- Set voltage adjust pot fully counterclockwise.
- Set gain to centered mid position.
- Set stability to centered mid position.
- Do not adjust underfrequency adjust initially.
- Set console voltage adjust potentiometer to mid position.
- Turn off all electrical loads and run engine at no-load.
- Adjust engine governor for 62 Hz on 60 Hz units or 51 Hz on 50 Hz units.
- Turn regulator voltage adjust pot to obtain desired line-to-line voltage per chart.
- If regulator lamp flashes, adjust stability pot until flashing stops.
- Apply load and adjust underfrequency adjust as desired.
- Check regulator lamp for flashing with load and adjust stability if needed.
- Adjust gain clockwise if better response needed, then correct instability with stability pot.
Tools required
Tool links are Amazon searches (affiliate links); manufacturer special tools may only be available from a dealer.
Specs & values
- 62 Hz no-load 60 Hz units
- 51 Hz no-load 50 Hz units
- desired line-to-line voltage per chart
Source: Generac service manual. Steps and values are as documented; always cross-check against the official manual and any later revisions for your exact serial number before servicing.