1GM10 start amps?

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tobble

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just upgrading the electrics system and trying to size a fuse for the engine starter. the cable is 35mm square, which according to my information is good for 130A continuous, and presuemably lots of amps momentary, i.e. when the starter moter, er, starts. according to the manual the starter is 60A, but presumeably the inrush is much greater.

has anyone actually measured the amps on a 1GM10 as you start cranking? If I get say a 125A, will that handle the inrush current and protect the cable? I've already got the fuse holder, one of the 'Mega' varieties, not sure if these are slow blow. putting in anything over the continuous rating of the cable seems a little pointless...

TIA
 
a useful site indeed, although the 200A Cold Cranking Amps suggested there for the battery doesn't necessarily come very near to the demand by the starter, especially as that figure covers the whole GM series and mine's the smallest! It also contradicts itself in a way, by suggesting using 100A welding cable - in practice this is fine, but it could do with a little explanation for the uninittiated.

at least I'm in line with their recommendations for cable size.

Thanks for the link though!
 
tobble said:
........especially as that figure covers the whole GM series and mine's the smallest! ..........
Click to expand...

I wondered about that too. Assuming that the difference across the range is the number of cylinders, I guess that it would take almost as much umph to get 1 pot through compression as 3 - especially as the compression strokes don't overlap.
 
tobble said:
If I get say a 125A, will that handle the inrush current and protect the cable? I've already got the fuse holder, one of the 'Mega' varieties, not sure if these are slow blow. putting in anything over the continuous rating of the cable seems a little pointless...
Click to expand...

Yes, Mega Fuses are "slow blow". You're unlikely to have a problem if you fit a 125A fuse.
 
tobble said:
just upgrading the electrics system and trying to size a fuse for the engine starter. the cable is 35mm square, which according to my information is good for 130A continuous, and presuemably lots of amps momentary, i.e. when the starter moter, er, starts. according to the manual the starter is 60A, but presumeably the inrush is much greater.

has anyone actually measured the amps on a 1GM10 as you start cranking? If I get say a 125A, will that handle the inrush current and protect the cable? I've already got the fuse holder, one of the 'Mega' varieties, not sure if these are slow blow. putting in anything over the continuous rating of the cable seems a little pointless...

TIA
Click to expand...
The Yanmar performance curve for the 1GM10 starter shows about 230 amps for max. output of 1kW and a stall current of 460 amps.
A 125 amp fuse is quite inadequate.
My feeling is to avoid fuses in starter circuits.
Edit:- the 60 amps you quote is the no-load current for the starter.
 
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earlybird said:
The Yanmar performance curve for the 1GM10 starter shows about 230 amps for max. output of 1kW and a stall current of 460 amps.
Click to expand...

Can you post a link for this please?

The 1GM10 is a baby engine, and I can't see that a 125A slow-blow fuse will be in any way inadequate. My Volvo 2003T is 43HP (versus 9HP for the 1GM10) and it works reliably with a 150A MegaFuse in the starting circuit.
 
pvb said:
Can you post a link for this please?

The 1GM10 is a baby engine, and I can't see that a 125A slow-blow fuse will be in any way inadequate. My Volvo 2003T is 43HP (versus 9HP for the 1GM10) and it works reliably with a 150A MegaFuse in the starting circuit.
Click to expand...

Figures are from the Yanmar workshop manual. Sorry, I haven't got a link to a PDF version. ( does VicS have one ?? )
The data are given in the form of curves for power, rpm, voltage and torque, all against current draw.
BTW:- the spec for the 34 hp 3HM35 starter, 1.8 kW, is 400amps and 800+ amps. stall.
Max. rating is for 30 seconds.
Peak output figures would be for a very cold day I guess!
 
I have the workshop manual, but couldn't see the information you describe. Maybe a different version of the book.

lots of conflicting advice here! sounds like I shall have to do it the empirical way - turn it over and see what happens...

will report back once I have an answer. thanks for your input guys
 
Starter motors don't have fuses? My Yanmar doesn't, nor did any vehicle I have ever owned.
What are you protecting against? If the motor jams solid and you persist in pushing the button, you get a horrid burning smell and eventually the motor or the cable burns out. But you'd release the button before that point, suspecting something was wrong.
 
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