Editing Openai/6944401e-07c8-800d-9890-76b35b1d919d (section)

=== Assistant: Got it — this helps a lot. ===
Got it — this helps a lot. Based on the panel photo and what you’re describing, this looks very much like a duplex pump system that ''can'' start both pumps together, which is exactly the kind of thing that will slam a generator on startup.

I’ll walk through what’s likely happening, then give you a practical startup procedure that usually works in the field.

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Key observations:
* Two motor contactors labeled M1 and M2 - These are full-voltage across-the-line starters (no soft start, no VFD)
* Two pump breakers labeled PUMP 1 (20A) and PUMP 2 (20A)
* Siemens LOGO! PLC - Almost certainly doing alternation, interlocks, and alarms
* Hand/Off/Auto selector switches for multiple subsystems
* No visible: - Soft starter - VFD - Reduced-voltage starter

===== Each pump likely pulls: =====
* 5–7× FLA on startup
* If both contactors close together (even briefly), the generator sees a huge inrush spike

On utility power you’d never notice.
On a generator → instant overload / stall / breaker trip.

==== One (or more) of these is happening: ====

===== This can happen if: =====
* PLC boots and initializes outputs simultaneously
* Lead/lag logic doesn’t delay the lag pump
* High-level float is already made at startup

===== - Generator struggles =====
* PLC browns out momentarily
* Outputs re-assert → both contactors pull in again

===== Even if: =====
* Running load is fine
* Starting load is not

==== This is the part you asked for directly. ====

===== Start only ONE pump, let the generator stabilize, then return to automatic control. =====

===== #### =====
* Put both Pump selectors to OFF (or MAN → OFF if that’s how they’re wired)
* Leave generator running unloaded for ~30–60 seconds

====== - Select Pump 1 → MAN ======
* Verify: - Generator does not bog - Voltage and frequency stabilize
* Let it run 30–60 seconds

====== Choose ONE: ======
* Leave Pump 2 selector in OFF
* Or trip Pump 2 breaker (preferred if selector logic is unclear)

This guarantees no simultaneous start.

====== - Generator is already under load ======
* PLC sees an already-running system, not a cold start

====== - Put selector back to AUTO ======
* Reset breaker if opened

At this point:
* Alternation will resume
* Generator will not see a double inrush

==== Then one of these is true: ====

===== Rule of thumb: =====
* Generator kVA should be ≥ 3–4× largest motor HP
* Duplex systems often need 5–6× if simultaneous start is possible

===== Common fix: =====
* Add time-delay relay on M2
* Or program PLC to: - Enforce 10–30s delay between pump starts

===== If the wet well is already high: =====
* PLC may intentionally start both pumps
* That’s fatal on a small generator

==== From simplest to best: ====
# Disable lag pump on generator power - Manual procedure or selector switch
# Add a start-delay relay to Pump 2
# Add a soft starter to at least one pump
# Reprogram PLC to enforce staggered starts
# Larger generator

==== - No, both pumps do not need to run for the system to function ====
* Yes, this panel is capable of starting both, which explains the generator overload
* Manual single-pump startup is the correct workaround
* This is a starting kVA problem, not a running load problem

If you want, tell me:
* Generator kW/kVA rating
* Pump HP (or model numbers)
* Whether this only happens after total power loss

I can sanity-check whether the generator is even theoretically capable of this setup.