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Fidd · 12-25-23, 08:50 PM

There is another technique which I think explains more how to avoid the trips blowing, which generally occurs if the motor-current either spikes suddenly, or reaches 800 amps:

From on electric motor - eg just surfaced:

1 Ensure diesel-clutches are disengaged.
2. Reduce e-motor rheostat to halfway position
3. Start diesels, (set compressor running) and warm diesels
4. Set e-motor direction to off
5. Set Parallel/Series (left to right)
6. Engage diesel clutch and bring to 350 rpm or so
7. Balance motor VOLTAGE and battery VOLTAGE using rheostat
8. Bring e-motor direction to forward
9. Adjust rheostat SLOWLY to full left (full charge direction) until Motor CURRENT remains below red line
10. If it does not reach the red-line, line, very slowly raise the diesel rpm. watching the relevant motor-current gauge on the over-head cluster, adjusting motor-current to the red line.

Notes (on similarly numbered points above):
1. Prevents too high an diesel rpm causing a transient spike in motor-current
2. Prevents the diesels causing a spike in (charging) motor-current, or a too rapid spike in motor-current as the slow relative shaft rpm of the emotor is suddenly asked to accelerate - which can cause a trip to blow even if the amperage doesn't reach 800.
3. Warming diesels before charging reduces likelihood of increased power as diesels warm of exceeding 800amps accidentally.
4. This allows you to balance motor and battery voltage (nil difference in voltage = nil current) before connecting the two
5. Needed for max rate charge
6. Prevents too much rpm causing spike in motor-current
7. ditto
8. Now you are charging - a bit
9. Now you are maxing motor-current to best possible charge rate for a given rpm
10. (may not be necessary, unless diesel rpm insufficient to make max charge)

If you want to develop a slow charge rate, but a better top speed, simply decide on a lower maximum motor-current limit, and adjust the rheostat in step 9 to that lower value. Now you are charging at a lower rate, but with a higher top speed. If you want an even higher top speed, consider an even lower maximum motor-current, or just charging on one engine. Probably best to warn the helm if you do that latter as it will play havoc with him holding a heading!

12-25-23, 08:50 PM	#5
Fidd XO Join Date: Apr 2005 Location: Blighty! Posts: 429 Downloads: 10 Uploads: 0	There is another technique which I think explains more how to avoid the trips blowing, which generally occurs if the motor-current either spikes suddenly, or reaches 800 amps: From on electric motor - eg just surfaced: 1 Ensure diesel-clutches are disengaged. 2. Reduce e-motor rheostat to halfway position 3. Start diesels, (set compressor running) and warm diesels 4. Set e-motor direction to off 5. Set Parallel/Series (left to right) 6. Engage diesel clutch and bring to 350 rpm or so 7. Balance motor VOLTAGE and battery VOLTAGE using rheostat 8. Bring e-motor direction to forward 9. Adjust rheostat SLOWLY to full left (full charge direction) until Motor CURRENT remains below red line 10. If it does not reach the red-line, line, very slowly raise the diesel rpm. watching the relevant motor-current gauge on the over-head cluster, adjusting motor-current to the red line. Notes (on similarly numbered points above): 1. Prevents too high an diesel rpm causing a transient spike in motor-current 2. Prevents the diesels causing a spike in (charging) motor-current, or a too rapid spike in motor-current as the slow relative shaft rpm of the emotor is suddenly asked to accelerate - which can cause a trip to blow even if the amperage doesn't reach 800. 3. Warming diesels before charging reduces likelihood of increased power as diesels warm of exceeding 800amps accidentally. 4. This allows you to balance motor and battery voltage (nil difference in voltage = nil current) before connecting the two 5. Needed for max rate charge 6. Prevents too much rpm causing spike in motor-current 7. ditto 8. Now you are charging - a bit 9. Now you are maxing motor-current to best possible charge rate for a given rpm 10. (may not be necessary, unless diesel rpm insufficient to make max charge) If you want to develop a slow charge rate, but a better top speed, simply decide on a lower maximum motor-current limit, and adjust the rheostat in step 9 to that lower value. Now you are charging at a lower rate, but with a higher top speed. If you want an even higher top speed, consider an even lower maximum motor-current, or just charging on one engine. Probably best to warn the helm if you do that latter as it will play havoc with him holding a heading!