Posted by Tim Jackson on June 13, 2009, 5:13 am
Ulysses wrote:
>> Ulysses wrote:
>>> I know what the field coil voltage normally is for a 12 volt,
>>> 3 phase alternator but couldn't find
>>> any such information on a 120 volt, single phase field coil. Maybe it
>>> should be obvious, but it's a mystery to me. Once I learn this it will
>>> probably be obvious.
>>>
>>>
>> The field coil voltage is entirely up to the designer of the alternator.
>> There is no 'standard' solution for an AC generator as there is no
>> convenient DC line to feed it from. The simplest design in most cases
>> is to use the rectified AC output, but it rather depends on the original
>> application. Measuring the coil's resistance should give you a clue, if
>> you calculate the voltage (sqrt(Watts*Ohms)) that will dissipate around
>> 5% of the alternator's rated output power, that shouldn't cook it and
>> should give plenty of field.
>>
>
> By "watts" do you mean the rated output of the alternator?
>
I mean the power you want it to dissipate, eg 5% of that. The general
ohms-law formula can be written as P = V**2/R, so what I wrote,
V = sqrt(P*R), is the way of getting calculating the voltage given the
power and resistance. You can measure the resistance and you can choose
the power. So the voltage you need to get your chosen field power is
what you calculate. What I am suggesting is you won't go far wrong if
you choose a field power of about 5% of the rated output power (and
calculate a voltage from that).
Tim
Posted by Ulysses on June 13, 2009, 11:46 am
> Ulysses wrote:
> >> Ulysses wrote:
> >>> I know what the field coil voltage normally is for a 12 volt,
> >>> 3 phase alternator but couldn't find
> >>> any such information on a 120 volt, single phase field coil. Maybe it
> >>> should be obvious, but it's a mystery to me. Once I learn this it
will
> >>> probably be obvious.
> >>>
> >>>
> >> The field coil voltage is entirely up to the designer of the
alternator.
> >> There is no 'standard' solution for an AC generator as there is no
> >> convenient DC line to feed it from. The simplest design in most cases
> >> is to use the rectified AC output, but it rather depends on the
original
> >> application. Measuring the coil's resistance should give you a clue,
if
> >> you calculate the voltage (sqrt(Watts*Ohms)) that will dissipate around
> >> 5% of the alternator's rated output power, that shouldn't cook it and
> >> should give plenty of field.
> >>
> >
> > By "watts" do you mean the rated output of the alternator?
> >
> I mean the power you want it to dissipate, eg 5% of that. The general
> ohms-law formula can be written as P = V**2/R, so what I wrote,
> V = sqrt(P*R), is the way of getting calculating the voltage given the
> power and resistance. You can measure the resistance and you can choose
> the power. So the voltage you need to get your chosen field power is
> what you calculate. What I am suggesting is you won't go far wrong if
> you choose a field power of about 5% of the rated output power (and
> calculate a voltage from that).
> Tim
OK, thanks :-D
Posted by harry on June 12, 2009, 2:52 pm
> >> > Anyone happen to know if the poles on a single phase alternator field
> > coil
> >> > (rotor) are opposite such as they are on a 3-phase alternator? I
> > applied
> >> > *some* voltage to it but don't know how much is OK and don't want to
> > burn
> >> > it
> >> > out but it seems, so far, that the poles are the same on both sides
> > (i.e.
> >> > N
> >> > and N and not N on one side and S on the other). Also, would the field
> >> > coil
> >> > be getting 120 volts on a 120/240 volt generator? I have this idea but
> >> > before I waste my time I need to find out why it won't work ;-)
> >> There should be one N and one S if it only has two poles. If more than
> >> that, it should alternate N, S, N, S and so on. The voltage applied to
> > the
> >> field winding is seldom anywhere near the same as the output voltage and
> >> it's always DC. (although once in a while the rectifier is mounted right
> > on
> >> the rotor so you can apply AC to the rotor's slip rings).
> >> Typical car alternator uses DC on the field winding, applied via two slip
> >> rings. Although it is only one coil, the metal pieces on each side have
> >> inter-woven fingers so that alternating 'fingers' are opposite polarity
> > (N,
> >> S, N, S as I mentioned above). One alternator has as many as 28
> >> 'fingers'
> >> so that's 14 N poles and 14 S poles, interwoven.
> >> Surprisingly, a rotor for a three-phase machine and a single-phase
> >> machine
> >> have the same number of poles and winding. The only difference between
> >> three-phase and single-phase is in the stator (armature) winding, not the
> >> rotor (field) winding.
> >> daestrom
> > What I have in mind is to use a field coil from a single-phase alternator
> > to
> > produce three-phase (or more) power by winding three coils (or six
> > perhaps)
> > for a new stator. This particular field coil has a tapered mount so it
> > would be direct-drive. It has slip rings so I could apply the excitation
> > current directly and control it for the desired output. That all depends
> > upon whether or not the coils are still OK. The generator I saved it from
> > had a melted stator but the field coils appear to be OK but I'm not sure
> > if
> > it's one coil wound on two poles or two seperate coils.
> It may be either. The important question is just how many magnetic poles it
> has. If it has one N and one S, it is a two-pole rotor. Two N's and two
> S's means four pole and so on. Call this number N. It must be an even
> number or you've got a consequent pole issue and I really, REALLY doubt that
> for an alternator rotor.
> If you want to wind a three-phase stator, you need 3*N number of coil groups
> (we call them pole-phase groups). Then the next thing to do is then count
> the slots in your stator (call it S) and hope that it is divisible by 3*N.
> If it is evenly divisible by 3*N then you are almost ready. You need to
> figure out how wide to make your coils (the coil pitch).
> Commercial machines we would put all the coils in with the leads extending
> out one end. The first few you leave one side of the coils 'up' out of the
> slot until you work your way around the stator. Put one side of each coil
> in the 'bottom' of a slot and move on. After you've put in one coil pitch
> worth, you can put one side in the bottom of the next slow and the other
> side in the 'top' of the first slot you started with, on top of the first
> coil you laid.
> After you have them all installed and wedged suitably tight in the slots,
> you figure out how many coils connect together to form one phase group. If
> you have a nice even stator, it comes out to S/(3*N). So a 72 slot stator,
> for a four pole machine, you have 72/(3*4) = 6 coils that you connect
> together into one phase group. When you're done with that step you should
> have 3*N (in my example 12) phase groups.
> Count off by 3 to see which ones are the same phase. If you imagine the
> rotor in the middle of the stator and one pole directly over one phase
> group, the other poles of the rotor will be directly over the other phase
> groups of the same phase.
> Connecting the individual phase groups together into each of the phases is
> not hard, but it's much easier to show with a diagram than to explain in
> words. But basically you can connect them either in series (more voltage)
> or parallel (more available current).
> BUt considering this is a seat-of-the-pants design, you might be best off by
> insulating the leads and assembling it first one time, spin it up and see
> how much voltage you get from one phase group. Then you can get an idea
> what it's capable of.
> If you want more current per coil but don't want to buy wire that is double
> in size, you can use an old trick we used of winding your coils
> 'two-in-hand'. Simply use two strands of the same size wire and wind both
> strands at the same time making half as many turns. You'll get half the
> voltage but by soldering the two strands together at each end you get double
> the cross-section.
> > Like I said I tried
> > applying some DC voltage and didn't get any definate answers but I did get
> > quite a zap when I disconnected the DC source so something is still
> > working.
> Big coil around iron is a great inductor :-)
> > All I would need to do is to make a brush holder, mount the non-engine end
> > in a bearing, and one way or another position the stator coils around it.
> > And rectify it, of course. Since there is some residual magnetism in the
> > field coil I think it will self-excite just like my Delco car alternator
> > does. But I don't know how much DC voltage it will need to excite and end
> > up producing, say, 80 volts at 3600 rpm, but I think that will be
> > controlled by the number of turns on the stator coils.
> The first thing you want to figure out is what is the max DC current you can
> push through the rotor. Take a look at the wire size to get an idea. Then
> start out with your trials using only about 25% of what you think the max
> is. This would be about the 'no-load field amps' operating point.
> As the load is applied to an AC alternator, the DC field current has to be
> increased quite a bit to keep the voltage constant.
> > To answer Jim
> > Wilkins the coil was originally for a single-phase, 120/240 3600 rpm
> > generator but I would be running it at 3600 maximum and slowing down the
> > engine to control my output voltage (and adjusting the field current as
> > needed too). Before I get started I just want to be pretty sure of what I
> > have to work with. It sounds like, from what everyone said, that the pole
> > should be correct for my purposes. :-D
> Okay, if it originally was 3600 rpm for 60Hz, then it is definitely a 2-pole
> rotor. So for three-phase you'll need six pole-phase groups.
> daestrom
It's fifty years since they made any sort of electrical machine to
thes principles. They were old fashioned when I was an apprentice. At
one time you could get them rewound, there were little motor rewind
shops in every town. Not any more. the stator is put in an autoclave,
a vacuum puled and epoxy resin srayed on. Then the vacuum is released
and it is baked. Stands the heat, mechanical forces and vibration
better than rewindable types.
Posted by daestrom on June 12, 2009, 5:09 pm
>>
>>
>>
>>
>>
>>
>>
>> >> > Anyone happen to know if the poles on a single phase alternator
>> >> > field
>> > coil
>> >> > (rotor) are opposite such as they are on a 3-phase alternator? I
>> > applied
>> >> > *some* voltage to it but don't know how much is OK and don't want to
>> > burn
>> >> > it
>> >> > out but it seems, so far, that the poles are the same on both sides
>> > (i.e.
>> >> > N
>> >> > and N and not N on one side and S on the other). Also, would the
>> >> > field
>> >> > coil
>> >> > be getting 120 volts on a 120/240 volt generator? I have this idea
>> >> > but
>> >> > before I waste my time I need to find out why it won't work ;-)
>>
>> >> There should be one N and one S if it only has two poles. If more
>> >> than
>> >> that, it should alternate N, S, N, S and so on. The voltage applied
>> >> to
>> > the
>> >> field winding is seldom anywhere near the same as the output voltage
>> >> and
>> >> it's always DC. (although once in a while the rectifier is mounted
>> >> right
>> > on
>> >> the rotor so you can apply AC to the rotor's slip rings).
>>
>> >> Typical car alternator uses DC on the field winding, applied via two
>> >> slip
>> >> rings. Although it is only one coil, the metal pieces on each side
>> >> have
>> >> inter-woven fingers so that alternating 'fingers' are opposite
>> >> polarity
>> > (N,
>> >> S, N, S as I mentioned above). One alternator has as many as 28
>> >> 'fingers'
>> >> so that's 14 N poles and 14 S poles, interwoven.
>>
>> >> Surprisingly, a rotor for a three-phase machine and a single-phase
>> >> machine
>> >> have the same number of poles and winding. The only difference
>> >> between
>> >> three-phase and single-phase is in the stator (armature) winding, not
>> >> the
>> >> rotor (field) winding.
>>
>> >> daestrom
>>
>> > What I have in mind is to use a field coil from a single-phase
>> > alternator
>> > to
>> > produce three-phase (or more) power by winding three coils (or six
>> > perhaps)
>> > for a new stator. This particular field coil has a tapered mount so it
>> > would be direct-drive. It has slip rings so I could apply the
>> > excitation
>> > current directly and control it for the desired output. That all
>> > depends
>> > upon whether or not the coils are still OK. The generator I saved it
>> > from
>> > had a melted stator but the field coils appear to be OK but I'm not
>> > sure
>> > if
>> > it's one coil wound on two poles or two seperate coils.
>>
>> It may be either. The important question is just how many magnetic poles
>> it
>> has. If it has one N and one S, it is a two-pole rotor. Two N's and two
>> S's means four pole and so on. Call this number N. It must be an even
>> number or you've got a consequent pole issue and I really, REALLY doubt
>> that
>> for an alternator rotor.
>>
>> If you want to wind a three-phase stator, you need 3*N number of coil
>> groups
>> (we call them pole-phase groups). Then the next thing to do is then
>> count
>> the slots in your stator (call it S) and hope that it is divisible by
>> 3*N.
>> If it is evenly divisible by 3*N then you are almost ready. You need to
>> figure out how wide to make your coils (the coil pitch).
>>
>> Commercial machines we would put all the coils in with the leads
>> extending
>> out one end. The first few you leave one side of the coils 'up' out of
>> the
>> slot until you work your way around the stator. Put one side of each
>> coil
>> in the 'bottom' of a slot and move on. After you've put in one coil
>> pitch
>> worth, you can put one side in the bottom of the next slow and the other
>> side in the 'top' of the first slot you started with, on top of the first
>> coil you laid.
>>
>> After you have them all installed and wedged suitably tight in the slots,
>> you figure out how many coils connect together to form one phase group.
>> If
>> you have a nice even stator, it comes out to S/(3*N). So a 72 slot
>> stator,
>> for a four pole machine, you have 72/(3*4) = 6 coils that you connect
>> together into one phase group. When you're done with that step you
>> should
>> have 3*N (in my example 12) phase groups.
>>
>> Count off by 3 to see which ones are the same phase. If you imagine the
>> rotor in the middle of the stator and one pole directly over one phase
>> group, the other poles of the rotor will be directly over the other phase
>> groups of the same phase.
>>
>> Connecting the individual phase groups together into each of the phases
>> is
>> not hard, but it's much easier to show with a diagram than to explain in
>> words. But basically you can connect them either in series (more
>> voltage)
>> or parallel (more available current).
>>
>> BUt considering this is a seat-of-the-pants design, you might be best off
>> by
>> insulating the leads and assembling it first one time, spin it up and see
>> how much voltage you get from one phase group. Then you can get an idea
>> what it's capable of.
>>
>> If you want more current per coil but don't want to buy wire that is
>> double
>> in size, you can use an old trick we used of winding your coils
>> 'two-in-hand'. Simply use two strands of the same size wire and wind
>> both
>> strands at the same time making half as many turns. You'll get half the
>> voltage but by soldering the two strands together at each end you get
>> double
>> the cross-section.
>>
>> > Like I said I tried
>> > applying some DC voltage and didn't get any definate answers but I did
>> > get
>> > quite a zap when I disconnected the DC source so something is still
>> > working.
>>
>> Big coil around iron is a great inductor :-)
>>
>> > All I would need to do is to make a brush holder, mount the non-engine
>> > end
>> > in a bearing, and one way or another position the stator coils around
>> > it.
>> > And rectify it, of course. Since there is some residual magnetism in
>> > the
>> > field coil I think it will self-excite just like my Delco car
>> > alternator
>> > does. But I don't know how much DC voltage it will need to excite and
>> > end
>> > up producing, say, 80 volts at 3600 rpm, but I think that will be
>> > controlled by the number of turns on the stator coils.
>>
>> The first thing you want to figure out is what is the max DC current you
>> can
>> push through the rotor. Take a look at the wire size to get an idea.
>> Then
>> start out with your trials using only about 25% of what you think the max
>> is. This would be about the 'no-load field amps' operating point.
>>
>> As the load is applied to an AC alternator, the DC field current has to
>> be
>> increased quite a bit to keep the voltage constant.
>>
>> > To answer Jim
>> > Wilkins the coil was originally for a single-phase, 120/240 3600 rpm
>> > generator but I would be running it at 3600 maximum and slowing down
>> > the
>> > engine to control my output voltage (and adjusting the field current as
>> > needed too). Before I get started I just want to be pretty sure of
>> > what I
>> > have to work with. It sounds like, from what everyone said, that the
>> > pole
>> > should be correct for my purposes. :-D
>>
>> Okay, if it originally was 3600 rpm for 60Hz, then it is definitely a
>> 2-pole
>> rotor. So for three-phase you'll need six pole-phase groups.
>>
>> daestrom
> It's fifty years since they made any sort of electrical machine to
> thes principles. They were old fashioned when I was an apprentice. At
> one time you could get them rewound, there were little motor rewind
> shops in every town. Not any more. the stator is put in an autoclave,
> a vacuum puled and epoxy resin srayed on. Then the vacuum is released
> and it is baked. Stands the heat, mechanical forces and vibration
> better than rewindable types.
Don't understand your point. You still have to wind the thing in the first
place. How you bake it and what type of insulation you use after the coils
are in the slots is a different matter all together.
OP wants to experiment with winding his own alternator. Not really cost
effective for a rewind shop, but if he wants to experiment, he has to know
how to wind and connect the coils.
daestrom
Posted by Ulysses on June 12, 2009, 7:10 pm
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> >> > Anyone happen to know if the poles on a single phase alternator
> >> >> > field
> >> > coil
> >> >> > (rotor) are opposite such as they are on a 3-phase alternator? I
> >> > applied
> >> >> > *some* voltage to it but don't know how much is OK and don't want
to
> >> > burn
> >> >> > it
> >> >> > out but it seems, so far, that the poles are the same on both
sides
> >> > (i.e.
> >> >> > N
> >> >> > and N and not N on one side and S on the other). Also, would the
> >> >> > field
> >> >> > coil
> >> >> > be getting 120 volts on a 120/240 volt generator? I have this
idea
> >> >> > but
> >> >> > before I waste my time I need to find out why it won't work ;-)
> >>
> >> >> There should be one N and one S if it only has two poles. If more
> >> >> than
> >> >> that, it should alternate N, S, N, S and so on. The voltage applied
> >> >> to
> >> > the
> >> >> field winding is seldom anywhere near the same as the output voltage
> >> >> and
> >> >> it's always DC. (although once in a while the rectifier is mounted
> >> >> right
> >> > on
> >> >> the rotor so you can apply AC to the rotor's slip rings).
> >>
> >> >> Typical car alternator uses DC on the field winding, applied via two
> >> >> slip
> >> >> rings. Although it is only one coil, the metal pieces on each side
> >> >> have
> >> >> inter-woven fingers so that alternating 'fingers' are opposite
> >> >> polarity
> >> > (N,
> >> >> S, N, S as I mentioned above). One alternator has as many as 28
> >> >> 'fingers'
> >> >> so that's 14 N poles and 14 S poles, interwoven.
> >>
> >> >> Surprisingly, a rotor for a three-phase machine and a single-phase
> >> >> machine
> >> >> have the same number of poles and winding. The only difference
> >> >> between
> >> >> three-phase and single-phase is in the stator (armature) winding,
not
> >> >> the
> >> >> rotor (field) winding.
> >>
> >> >> daestrom
> >>
> >> > What I have in mind is to use a field coil from a single-phase
> >> > alternator
> >> > to
> >> > produce three-phase (or more) power by winding three coils (or six
> >> > perhaps)
> >> > for a new stator. This particular field coil has a tapered mount so
it
> >> > would be direct-drive. It has slip rings so I could apply the
> >> > excitation
> >> > current directly and control it for the desired output. That all
> >> > depends
> >> > upon whether or not the coils are still OK. The generator I saved it
> >> > from
> >> > had a melted stator but the field coils appear to be OK but I'm not
> >> > sure
> >> > if
> >> > it's one coil wound on two poles or two seperate coils.
> >>
> >> It may be either. The important question is just how many magnetic
poles
> >> it
> >> has. If it has one N and one S, it is a two-pole rotor. Two N's and
two
> >> S's means four pole and so on. Call this number N. It must be an even
> >> number or you've got a consequent pole issue and I really, REALLY doubt
> >> that
> >> for an alternator rotor.
> >>
> >> If you want to wind a three-phase stator, you need 3*N number of coil
> >> groups
> >> (we call them pole-phase groups). Then the next thing to do is then
> >> count
> >> the slots in your stator (call it S) and hope that it is divisible by
> >> 3*N.
> >> If it is evenly divisible by 3*N then you are almost ready. You need
to
> >> figure out how wide to make your coils (the coil pitch).
> >>
> >> Commercial machines we would put all the coils in with the leads
> >> extending
> >> out one end. The first few you leave one side of the coils 'up' out of
> >> the
> >> slot until you work your way around the stator. Put one side of each
> >> coil
> >> in the 'bottom' of a slot and move on. After you've put in one coil
> >> pitch
> >> worth, you can put one side in the bottom of the next slow and the
other
> >> side in the 'top' of the first slot you started with, on top of the
first
> >> coil you laid.
> >>
> >> After you have them all installed and wedged suitably tight in the
slots,
> >> you figure out how many coils connect together to form one phase group.
> >> If
> >> you have a nice even stator, it comes out to S/(3*N). So a 72 slot
> >> stator,
> >> for a four pole machine, you have 72/(3*4) = 6 coils that you connect
> >> together into one phase group. When you're done with that step you
> >> should
> >> have 3*N (in my example 12) phase groups.
> >>
> >> Count off by 3 to see which ones are the same phase. If you imagine
the
> >> rotor in the middle of the stator and one pole directly over one phase
> >> group, the other poles of the rotor will be directly over the other
phase
> >> groups of the same phase.
> >>
> >> Connecting the individual phase groups together into each of the phases
> >> is
> >> not hard, but it's much easier to show with a diagram than to explain
in
> >> words. But basically you can connect them either in series (more
> >> voltage)
> >> or parallel (more available current).
> >>
> >> BUt considering this is a seat-of-the-pants design, you might be best
off
> >> by
> >> insulating the leads and assembling it first one time, spin it up and
see
> >> how much voltage you get from one phase group. Then you can get an
idea
> >> what it's capable of.
> >>
> >> If you want more current per coil but don't want to buy wire that is
> >> double
> >> in size, you can use an old trick we used of winding your coils
> >> 'two-in-hand'. Simply use two strands of the same size wire and wind
> >> both
> >> strands at the same time making half as many turns. You'll get half
the
> >> voltage but by soldering the two strands together at each end you get
> >> double
> >> the cross-section.
> >>
> >> > Like I said I tried
> >> > applying some DC voltage and didn't get any definate answers but I
did
> >> > get
> >> > quite a zap when I disconnected the DC source so something is still
> >> > working.
> >>
> >> Big coil around iron is a great inductor :-)
> >>
> >> > All I would need to do is to make a brush holder, mount the
non-engine
> >> > end
> >> > in a bearing, and one way or another position the stator coils around
> >> > it.
> >> > And rectify it, of course. Since there is some residual magnetism in
> >> > the
> >> > field coil I think it will self-excite just like my Delco car
> >> > alternator
> >> > does. But I don't know how much DC voltage it will need to excite
and
> >> > end
> >> > up producing, say, 80 volts at 3600 rpm, but I think that will be
> >> > controlled by the number of turns on the stator coils.
> >>
> >> The first thing you want to figure out is what is the max DC current
you
> >> can
> >> push through the rotor. Take a look at the wire size to get an idea.
> >> Then
> >> start out with your trials using only about 25% of what you think the
max
> >> is. This would be about the 'no-load field amps' operating point.
> >>
> >> As the load is applied to an AC alternator, the DC field current has to
> >> be
> >> increased quite a bit to keep the voltage constant.
> >>
> >> > To answer Jim
> >> > Wilkins the coil was originally for a single-phase, 120/240 3600 rpm
> >> > generator but I would be running it at 3600 maximum and slowing down
> >> > the
> >> > engine to control my output voltage (and adjusting the field current
as
> >> > needed too). Before I get started I just want to be pretty sure of
> >> > what I
> >> > have to work with. It sounds like, from what everyone said, that the
> >> > pole
> >> > should be correct for my purposes. :-D
> >>
> >> Okay, if it originally was 3600 rpm for 60Hz, then it is definitely a
> >> 2-pole
> >> rotor. So for three-phase you'll need six pole-phase groups.
> >>
> >> daestrom
> >
> > It's fifty years since they made any sort of electrical machine to
> > thes principles. They were old fashioned when I was an apprentice. At
> > one time you could get them rewound, there were little motor rewind
> > shops in every town. Not any more. the stator is put in an autoclave,
> > a vacuum puled and epoxy resin srayed on. Then the vacuum is released
> > and it is baked. Stands the heat, mechanical forces and vibration
> > better than rewindable types.
> Don't understand your point. You still have to wind the thing in the
first
> place. How you bake it and what type of insulation you use after the
coils
> are in the slots is a different matter all together.
> OP wants to experiment with winding his own alternator. Not really cost
> effective for a rewind shop, but if he wants to experiment, he has to know
> how to wind and connect the coils.
> daestrom
So far, with 12 volts attached to the rotor (field core) I have not been
able to establish the direction of the poles or verify that it is indeed an
electromagnet. I tried placing a permanant magnet on each pole and applying
voltage to the slip rings and get nothing. It seem like both poles are
either N or S based upon the attraction/repulsion of the magnet. I guess I
need more volts. I think my digital multimeter is not working.
I found some specific information on how to rewind a Delco alternator stator
but the maximum wire size that will fit in there is only about #25 and it is
my understanding that I will then have twice the voltage at a given rpm but
I'll end up with only half the current with the small wire size. My making
my own stator for the single phase rotor that I have on hand I can use more
turns of bigger wire. But I'm not going to build anything until I can be
pretty sure the field coils even work ;-)
My ultimate goal is to come up with some kind of direct-drive alternator to
charge my 48 volt battery bank using a small engine. My Delco 10SI
alternator would be adequate with the stock stator if only I could find a
way to drive it reliably. I figure direct-drive=no more belt problems. If
I run it past about 25-30 amps the belt becomes a problem but I have managed
to get about 60 amps at over 50 volts out of the thing without frying the
diodes so the alternator is good. Maybe I should try a chain drive again
with some better couplings.
XML site map
>>> I know what the field coil voltage normally is for a 12 volt,