question about rectifier ....

[free boat rides 4 sale]

I have a 1978 merc 1150, the tower of power. I am in school and learning about ac/dc circuits. I am wondering, if I want to increase the output voltage to my battery while the motor is running, would I have to build my own rectifier, or is there an aftermarket, or even OEM part of a newer Merc motor that I could put on my motor ?

I "think" my rectifier puts out 6 amps. That is just some number that comes off top of my head. Not sure if I read that or heard that. BUt I wondering about increasing it.
So, is it safe to increase the output? Is is advisable to leave it alone ?

Mr. M

 

[j_martin]

Re: question about rectifier ....

I have a 1978 merc 1150, the tower of power. I am in school and learning about ac/dc circuits. I am wondering, if I want to increase the output voltage to my battery while the motor is running, would I have to build my own rectifier, or is there an aftermarket, or even OEM part of a newer Merc motor that I could put on my motor ?

I "think" my rectifier puts out 6 amps. That is just some number that comes off top of my head. Not sure if I read that or heard that. BUt I wondering about increasing it.
So, is it safe to increase the output? Is is advisable to leave it alone ?

Mr. M

Peak power in a simple rectifier system like this is determined by the mechanical design of the stator. It's probably 16 amps.

The rectifier just switches the power. It doesn't increase or decrease it.

You may have a shunt regulator on the motor. If it is defective, it could be shunting some of the power needed for the battery. On a low amperage system, the battery itself can serve as the voltage regulator as long as it is regularly maintained. It will use water.

hope it helps
John

 

[jimg984]

Re: question about rectifier ....

http://www.mouser.com/Search/Refine...nalKeyword=640-36mb-120a&Ntk=Mouser_Wildcards........... this a heavy duty rectifier, i will not produce higher amperage,however it will take more abuse, abuse meanig dirty connection on wiring worst thing being taking either battery cable off with the motor running

 

[free boat rides 4 sale]

Re: question about rectifier ....

Peak power in a simple rectifier system like this is determined by the mechanical design of the stator. It's probably 16 amps.

The rectifier just switches the power. It doesn't increase or decrease it.

You may have a shunt regulator on the motor. If it is defective, it could be shunting some of the power needed for the battery. On a low amperage system, the battery itself can serve as the voltage regulator as long as it is regularly maintained. It will use water.

hope it helps
John

John, what is a shunt regulator ? Where is it located ? How do I find out if my system is low amperage ?
My stator has two wires coming from it. How do I find out what it is outputting ? Will the output fluxuate with motor rpm ?

Mr. M

 

[j_martin]

Re: question about rectifier ....

If it's an inline, it's low amperage, like 13 or 16 amps. Open circuit, the stator will put out 10 - 15 volts per 1000 rpm. It's a fairly low impedance until the magnetics saturate, which limits the output by design.

Hang a bridge rectifier on it, put an automotive ammeter in the red lead, and see what it puts out.

If you have a wire going to some cube module from the battery terminal on the rectifier, it is probably a shunt regulator. I don't think they used them on the tower. You see them on some V6's.

hope it helps
John

 

[jimg984]

Re: question about rectifier ....

9 amps at WOT no regulator i own a 1978 115 tower of power
a good charged battery before i leave home will start motor and out last my money for gas lol

 

[j_martin]

Re: question about rectifier ....

9 amps at WOT no regulator i own a 1978 115 tower of power
a good charged battery before i leave home will start motor and out last my money for gas lol

There ya go. Ya need a good battery and shore power charging when you're sleeping unless you run wide open all the time and never move the trim.

 

[zinc]

Re: question about rectifier ....

I have a 1978 merc 1150, the tower of power. I am in school and learning about ac/dc circuits. I am wondering, if I want to increase the output voltage to my battery while the motor is running, would I have to build my own rectifier, or is there an aftermarket, or even OEM part of a newer Merc motor that I could put on my motor ?

I "think" my rectifier puts out 6 amps. That is just some number that comes off top of my head. Not sure if I read that or heard that. BUt I wondering about increasing it.
So, is it safe to increase the output? Is is advisable to leave it alone ?

Mr. M

This is up my alley...........
Mercury uses a bridge rectifier, the unit looks like a diamond with 3 studs on it and the base of it is ground ( - ) in which there are 2 Zener diodes 2 regular diodes...the diodes take AC (back and forth) current coming from the flywheel alternator and rectified the current to DC ( direct current), the 2 Zener diodes regulate the current by shunting to ground when the Zener current is reached.....please see schematic.
The shop manual calls for 10 to 12 amps output at 5000 rpm's.
Good luck on your Ac/Dc course.

 

[Chris1956]

Re: question about rectifier ....

Zinc, Are you sure Merc uses zener diodes in their rectifier? I had thought it was a standard bridge rectifier with the DC neg pole grounded.

As far as I know those Mercs were unregulated with at most 9A output. This charging is adequate for boats with "lite" electronics. A 1978 Merc 1150 should have the batery driven ign system, however charging is still adequate.

 

[free boat rides 4 sale]

Re: question about rectifier ....

What I have is two wires from stator going to rectifier. And a separate wire from the rectifier going to the lead of the battery that is attached to the starter silenoid. So total of 3 wires on my rectifier.

 

[Laddies]

Re: question about rectifier ....

All inline 6s thru 79 had a simple 9 amp system there were no other types built, some seasoned stators will put out as high as 10 to 12 amps here's the alternator sheet for your engine.

 

[free boat rides 4 sale]

Re: question about rectifier ....

Hey Laddies, Oh thank you so very much. I asked my instructor this morning in class about a rectifier and he drew on board pretty much what you gave me here. I understood what he was saying and I asked about testing and such. And your info just put icing on the cake.

Thank you man. God Bless. Mr. M

 

[zinc]

Re: question about rectifier ....

Zinc, Are you sure Merc uses zener diodes in their rectifier? I had thought it was a standard bridge rectifier with the DC neg pole grounded.

As far as I know those Mercs were unregulated with at most 9A output. This charging is adequate for boats with "lite" electronics. A 1978 Merc 1150 should have the batery driven ign system, however charging is still adequate.

Yeah.....
I saw the setup in the schematics from the shop manual and said the same thing about there being 2 Zener diodes in there along with 2 regular diodes hooked up in a bridge fashion.
(Reference SELOC REPAIR MANUAL,part #1406, page# A-24)

 

[zinc]

Re: question about rectifier ....

Zinc, Are you sure Merc uses zener diodes in their rectifier? I had thought it was a standard bridge rectifier with the DC neg pole grounded.

As far as I know those Mercs were unregulated with at most 9A output. This charging is adequate for boats with "lite" electronics. A 1978 Merc 1150 should have the batery driven ign system, however charging is still adequate.

All inline 6s thru 79 had a simple 9 amp system there were no other types built, some seasoned stators will put out as high as 10 to 12 amps here's the alternator sheet for your engine.

Thank you Laddies.....
Just a note....your schematic shows a full wave bridge rectifier, where as in my schematic shows the same "BUT" 2 of those diodes are Zeners,
About half way down your page "THEORY OF OPERATION"
The voltage is regulated by "shorting one stator lead to ground"
A regular diode will not do this, hence the reason for the Zener diode.

 

[Laddies]

Re: question about rectifier ....

The rectifiers use 4 standard diodes and the early regulators used zener diodes as a voltage control that drawing is from a Mercury Marine handout and they probably have a better idea whats in thier rectifiers than Seloc.