Overcharged but won't turn starter?????

OK, Thanks. I can do that! but where does RMS (x 1.414) come from

 

OK. You asked!

RMS is the acronym for Root Mean Square Now read on........

To calculate the RMS value of a sine wave, multiply the peak value by 0.707. The peak value is, of course, one half the peak-to-peak value. To go the other way, reverse the order of operations. That is, if you're starting with an RMS value, divide by 0.707 and then multiply by two to get the p-p value. Another way to convert from RMS to p-p is to multiply the RMS value by two square roots of two: RMS x 2 x SQR(2).


Or more simply, to convert from RMS to peak to peak voltage:

(RMS x 1.414) x 2=P-P

For example:

120vac x 1.414= 170vac 170 vac x 2 = 340 vac P-P

 

WaMax, you rock!

 

i think it comes from Mars
doesn't really matter, meters read AC in RMS volts, oscilloscopes read AC Peak to Peak and are usually noted p-p
DC volts are just DC volts, well not really but close enough for us

 

OK, pass the paracetamol...
the last bit looks do-able.
So I can use the figure 1.414 for this test?
The 120vac figure, is that the total of the three readings at the connecter?
I'm not really that stoopid, I did start an electronics course at school but when I found out I was colour blind it kind of put an end to that idea :roll: so I didn't get to learn this stuff.

 

So these guys have been frying my brain just for a laugh??
Actually I was going to mention that about meters, I want to talk to you I think, my head is happier with your language
so I stick the red bit on the bit with the little cross and the black bit on the bit with the line....

 

"So these guys have been frying my brain just for a laugh??" no everything everyone told you is the truth
right now the best thing to do is measure your ac on the 3 wires and write them down for future reference, your getting the right volts out so the right volts must be going in, case closed, move on
i don't think it's a good idea to run it with the alternator unplugged
do something easy like set your floats or shim the valves

 

If only this were so, you have to pay more for a meter that will do this. Not all can.

Yup, quite so. They also read DC.

From an XJ perspective you are right. There is always a small bit of ripple on the rectified DC but it causes no issues other than a bit of hum on the stereo that I installed without a filter. A trip to Radio Shack fixed that.
Jay, make the list that Polock showed you and measure the output of the alternator by poking the meter leads into the connector housing. Not a good idea to run the alternator with it disconnected.

 

"do something easy like set your floats or shim the valves"
If ain't broke don't fix it!
I'm waiting for a YICS tool now, (I can get one for £25 ($40 ish)
as carb sync is the only issue pending.
I will need a new front tyre in a few weeks it needs matching to the rear (Shinko) anyway - it does'nt like white lines!