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Not a problem.
Old 03-07-2006, 06:54 AM   #6 (permalink)
JonScott
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You can safely power four of the B800 units (for example) with a 4.5 kW generator. I think you are going to have enough fault tolerance in a standard generator set to avoid any major problems.

Use a surge arrestor, if there isn't one already in the load center of the generator set.

Don't be overly concerned about waveform distortion. The bees are pretty tolerant of line distortion, as long as the generator isn't producing square waves and the crest factor is close to that of a sine wave (a true sine wave generator is of course perfect, but those are $pendy).

The generator should be at least voltage-limited so that it doesn't start producing an output of over 130 volts when momentarily overloaded; keep in mind that the lights will draw nearly 18 Amperes each for the first ten or fifteen ac cycles when the capacitors are being recharged. The current is the same, regardless of the power setting, and it just lasts for a shorter period of time when the power is reduced.

Ideally, one would use a constant current or current limiting regulated generator; the Bees don't mind voltage sags, and will just happily charge their capacitors at whatever current one wishes to provide, assuming the RMS voltage doesn't dip below about 85.

If push comes to shove, the whole swarm of bees can be sourced through an ac capacitor bank, sized for the maximum generator output: for 4.5 kW, that would be, what, about 800 uF sounds right, so make it 4X 200 uF motor-run 120 VAC caps in parallel. Shunt the capacitor bank with a 7-1/2 Watt light bulb to provide a resistive return for the control circuitry, and you're set to go. I really don't think you will need to resort to that, though.

- Micheal Morgan, PCB R&D supervisor
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