is the xr400 12v ac or dc?
Discussion
Both!!
The output of the stator will be AC. The output of your rectifier will be DC. Thats what a rectifier does, it takes AC and converts to DC in either half wave or full wave rectification and it's input wont be 12v. Typically 25VAC+ as the rectification lowers the voltage. The lack of battery isn't an issue, but rather the wattage output of the stator(generator) and the normal current consuption. Knowing these will allow you to calculate wheter you can run anything else. If the load is higher than the supply, a battery will assist if the excess load is brief, but if constant will run low.
Is this still the indictors??
see this for an explanation especially the 3 phase rectification bit http://www.allaboutcircuits.com/vol_3/chpt_3/4.htm...
The output of the stator will be AC. The output of your rectifier will be DC. Thats what a rectifier does, it takes AC and converts to DC in either half wave or full wave rectification and it's input wont be 12v. Typically 25VAC+ as the rectification lowers the voltage. The lack of battery isn't an issue, but rather the wattage output of the stator(generator) and the normal current consuption. Knowing these will allow you to calculate wheter you can run anything else. If the load is higher than the supply, a battery will assist if the excess load is brief, but if constant will run low.
Is this still the indictors??
see this for an explanation especially the 3 phase rectification bit http://www.allaboutcircuits.com/vol_3/chpt_3/4.htm...
Edited by bass gt3 on Wednesday 27th February 14:32
bass gt3 said:
The output of the stator will be AC. The output of your rectifier should be DC. Thats what a rectifier does, it takes AC and converts to DC in either half wave or full wave rectification and it's input wont be 12v. Typically 25VAC+ as the rectification lowers the voltage
see this for an explanation especially the 3 phase rectification bit http://www.allaboutcircuits.com/vol_3/chpt_3/4.htm...
Whats the issue?
Wot he said.see this for an explanation especially the 3 phase rectification bit http://www.allaboutcircuits.com/vol_3/chpt_3/4.htm...
Whats the issue?
Edited by bass gt3 on Wednesday 27th February 14:24
VinceFox said:
i'm going to end up having to use a battery pack aren't i?
No, not necessarily! You need to do some maffs and stuff, but it's easy! If you can determine the output of the stator/generator in Watts, and that of the rectfier, with a DMM 9digital multi meter) you can find out the total consumption of the bike with all electrics on and calculate any headroom for extras. By calculating the same for the indicator bulbs and relay, you'll know if it'll work. If the load exceeds the systems supply capacity, a batery will help buffer the load from the coil and not affect the running of the bike.Mail me if you need any help
bass gt3 said:
VinceFox said:
i'm going to end up having to use a battery pack aren't i?
No, not necessarily! You need to do some maffs and stuff, but it's easy! If you can determine the output of the stator/generator in Watts, and that of the rectfier, with a DMM 9digital multi meter) you can find out the total consumption of the bike with all electrics on and calculate any headroom for extras. By calculating the same for the indicator bulbs and relay, you'll know if it'll work. If the load exceeds the systems supply capacity, a batery will help buffer the load from the coil and not affect the running of the bike.VidalBaboon said:
Could you get away with using a diode & a capacitor as a make-shift rectifier?
In this instance, it's not necessary. The bike will have a rectifier which is a half or full wave rectifier. I suspect it's a half wave with poor ripple filtering but thats immaterial. It's all about load. Amps/Watts/Joules.
example:
If the bikes generator produces 3 phase AC at 25VAC and can supply a load of 60watts into the rectifier, the then you're going to get 12VDC out with a load capacity of circa 55/50 Watts. The loss is typically heat from the rectifier.
So if the bikes total consumption with all possible loads like engine running, headlights on, brake lights on etc is 35 Watts, then you have a theoretical headspace of 15-20 Watts of surplus supply capacity.
If you attach a load that draws 30 watts, you're now drawing 65 Watts from a device not rated to supply it. So whilst it will supply the power as best it can, the voltage will drop and may cause the engine to run badly due to reduced coil voltage. Don't forget that the coil is a large ratio step up transformer so any small drop on the input side will have a huge effect on the output voltage.
So if this new total load exceeds the bikes capacity to supply power, a battery will help supply the excess load for a duration. If the load is constant, the battery will drain. If the load is brief, the battery will support the load then go back to charging when the excess load is removed.
Remeber that heat is the enemy, and overloading will drive up component temps, which causes a phenomenon called thermal runaway. As heat increase, so does resistance. Higher resistance causes more heat which in turn causes more resistance.... You see whats goingot happen. Eventually, there's component failure and it's usually the rectifier. It's why Honda had issues. Load imbalance from genny supply to rec load causes thermal overload and failure
The theory is simple. You can't get a quart from a pint pot.
Edited by bass gt3 on Wednesday 27th February 15:03
bass gt3 said:
VidalBaboon said:
Could you get away with using a diode & a capacitor as a make-shift rectifier?
In this instance, it's not necessary. The bike will have a rectifier which is a half or full wave rectifier. I suspect it's a half wave with poor ripple filtering but thats immaterial. It's all about load. Amps/Watts/Joules.
example:
If the bikes generator produces 3 phase AC at 25VAC and can supply a load of 60watts into the rectifier, the then you're going to get 12VDC out with a load capacity of circa 55/50 Watts. The loss is typically heat from the rectifier.
So if the bikes total consumption with all possible loads like engine running, headlights on, brake lights on etc is 35 Watts, then you have a theoretical headspace of 15-20 Watts of surplus supply capacity.
If you attach a load that draws 30 watts, you're now drawing 65 Watts from a device not rated to supply it. So whilst it will supply the power as best it can, the voltage will drop and may cause the engine to run badly due to reduced coil voltage. Don't forget that the coil is a large ratio step up transformer so any small drop on the input side will have a huge effect on the output voltage.
So if this new total load exceeds the bikes capacity to supply power, a battery will help supply the excess load for a duration. If the load is constant, the battery will drain. If the load is brief, the battery will support the load then go back to charging when the excess load is removed.
Remeber that heat is the enemy, and overloading will drive up component temps, which causes a phenomenon called thermal runaway. As heat increase, so does resistance. Higher resistance causes more heat which in turn causes more resistance.... You see whats goingot happen. Eventually, there's component failure and it's usually the rectifier. It's why Honda had issues. Load imbalance from genny supply to rec load causes thermal overload and failure
The theory is simple. You can't get a quart from a pint pot.
Edited by bass gt3 on Wednesday 27th February 15:03
StuB said:
Honda sold XR400's in enduro spec with & without light kits. I doubt they changed the generator between variants if that helps, but a part search will tell you. I remember the output at tickover was barely visible lights, even in the dark.
That's the same with mine, it's noticably dimmer on tickover. Ive heard of uprated stator winding thingies giving more power, that might be something else i need to do.
VinceFox said:
How much do you charge and are you anywhere near dorset?
i don't charge but i'm nowhere near Dorset sadly. The closest i got was growing up next door to Brands Hatch but currently living in SA.Trust me, it's really simple. Don't go by what the generator puts out at tickover. The coils aren't excited enough to make power, so it's output will be rated at a nominal rpm, such as 3k. Higher speed equals higher output voltage due to Tesla's left/right hand rule (forget which!!)
So, here's what you do, and listen carefully, i will only say zis once!!
Get a pair of indicators and your flasher relay and wire them up loosely. Make temp twist joints and lay on the floor by the bike. Now, using the Mk1 eyeball, find the regulator/rectifier. The wires coming in from the stator are AC. You don't want these. Find the other wires. One will be a ground as it'll be earthed close to the reg/rec. Depending on the reg/rec, there'll be another wire or more coming out. This/These are positives and are of interest to you. As discretely as possible, hook up to the +ve and take the -ves from the indicators and flasher relay to ground somewhere. Now run the bike at a nomoinal rpm, maybe 2k, or higher. activate the indicator switchand check both indicators are flashing within the required time pulse. If it's too slow, the voltage is too low and the flasher relay isn't energising properly. Too fast? Check that BOTH indicators are flashing. Depending on the type of flashed relay, some use the indicators as a load to regulate the relay.
Now, if it works ok, and the bike isn't stuttering when all the lights are on, brake light on, horn on, everything going, there's enough reserve in the stator to run the bike. If it suffers, try hooking a battery across the +ve you took the indicator feed from and -ve.
Try this at various rpm's including tickover and see what happens. If it's all slow and blinky at tickover, then check if thisis ok for an MOT and stop stressing. If not ok, try upping the idle a fraction. it doesn't take much difference in speed to excite the coils and produce more power.
So, hopefully you'll find that it works ok without the battery, but if needed, just hook it as described and put a fuse in line. it can't discharge through the rectifier as it's a diode bridge so wont allow backwards voltage.
So the wiring is as follows-
attach a wire to the +ve from the rec/reg
attach the other end of this wire to the input of the flasher relay
attach the output of the flasher relay to the common of the indicator switch
attach one of the indicator switch outputs to a wire.
connect BOTH indicator bulbs to thsi wire. it must be a parallel circuit NOT series.
Take the other side of the indictor bulbs to -ve.
you're wired!!
now run the bike & test. if nothing happens, change the input/output of the flasher relay as these can be polarity sensitive.
Have a beer and celebrate your new found electrickey skills.
Donate a couple of quid to your favourite charity for me..
Carry on.
Edited by bass gt3 on Wednesday 27th February 21:15
VinceFox said:
Virtual beer sir, thank you.
I may be back with photos. Some of them of burnt fingers.
Pleasure fella. If you want, drop me a mail and i'll send you a diagram for you to follow. But check my edit as it beaks it down by sections. V Easy.I may be back with photos. Some of them of burnt fingers.
And when in doubt, remember the following......
Red to Black......Blue to bits!!
bass gt3 said:
VinceFox said:
Virtual beer sir, thank you.
I may be back with photos. Some of them of burnt fingers.
Pleasure fella. If you want, drop me a mail and i'll send you a diagram for you to follow. But check my edit as it beaks it down by sections. V Easy.I may be back with photos. Some of them of burnt fingers.
And when in doubt, remember the following......
Red to Black......Blue to bits!!
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