Tit that I am.

[Big Jets]

I was checking my Generator bulb ,as I had a problem with my charging ,silly cnut me I dropped the fecker and it broke ,anyway ive since fitted a new rotor bike ready for a run on Saturday apart from one small item a 3 watt bulb ,I can get 2 amp ones in fact I got one ,I am waiting for one (3 watt) coming from Motorworks but they are ordering it in for me ,would a 2watt one be ok or do I need the rite one full stop.

 

[pablo666]

well IMHO if it's rated at 3 watts then a 2 watt bulb should blow since it's likely to be overloaded, but and a big but at that, when the manufacturer rated it at a 3 watt bulb there was likely to be a bit of a safety margin and the 2 watt bulb may be able to handle a bit more power at a shorter life span........In short, try it and see

 

[nud1e]

The other lamps are 3W, so I used the lamp from the indicator to replace the generator lamp and used a 2W in the indicator.

 

[Big Jets]

Tried that Nudie they are all 2 Watt

 

[Womble]

A quick bit of googling and I think I can see what the problem is, assuming that you're trying to make sure that the system still charges without damaging the circuit.

The page I was looking at for Alternator Gen Lamp Circuit Modifications talks about being able to add a 470 or 330 ohm resistor across the back of the bulb, which will allow the charging circuit to work, even if the bulb blows. Adding the 330 ohm bulb barely increases the wattage, but without the bulb, it runs at 0.04 W and the bike still charges.

Without too many sums, a load of 3W and under looks safe, so bunging in a 2W bulb should be perfectly safe until you source the proper one. I suspect that the reason the 3W bulb is used is because a 2W bulb won't quite be bright enough, and it's just so you can see it in daylight - in the generator circuit it's in line with the alternator winding, so it doesn't have the full 12V across it, unlike the other bulbs. You can probably run it forever like that - in fact the bulb may even last longer that the 3W one.

...and now someone will pop along to tell me how wrong I am

 

[John Armstrong]

Tried that Nudie they are all 2 Watt

I was under the impression that they were either 1.2 or 3 watt

 

[(RIP) Proff]

A quick bit of googling and I think I can see what the problem is, assuming that you're trying to make sure that the system still charges without damaging the circuit.

The page I was looking at for Alternator Gen Lamp Circuit Modifications talks about being able to add a 470 or 330 ohm resistor across the back of the bulb, which will allow the charging circuit to work, even if the bulb blows. Adding the 330 ohm bulb barely increases the wattage, but without the bulb, it runs at 0.04 W and the bike still charges.

Without too many sums, a load of 3W and under looks safe, so bunging in a 2W bulb should be perfectly safe until you source the proper one. I suspect that the reason the 3W bulb is used is because a 2W bulb won't quite be bright enough, and it's just so you can see it in daylight - in the generator circuit it's in line with the alternator winding, so it doesn't have the full 12V across it, unlike the other bulbs. You can probably run it forever like that - in fact the bulb may even last longer that the 3W one.

...and now someone will pop along to tell me how wrong I am

Nope, quite correct, all the older airheads from 60's onwards had the 2w genny light