Customer Support 7 days a week

Welcome Guest! To enable all features please Login or Register.

Notification

Icon
Error

Post a reply
From:
Message:

Maximum number of characters in each post is: 32767
Bold Italic Underline   Highlight Quote Choose Language for Syntax Highlighting Insert Image Create Link   Unordered List Ordered List   Left Justify Center Justify Right Justify   Outdent Indent   More BBCode Tags
Font Color Font Size
Security Image:
Enter The Letters From The Security Image:
  Preview Post Cancel

Last 10 Posts (In reverse order)
Earl Dryer Posted: Thursday, November 20, 2008 4:50:45 PM(UTC)
 
Icehouse, you are exactly right on 3 wire systems and potential differences of such systems, that is why you sometimes get shocked when you touch a neutral and something grounded. I just thought it was odd that L1 to Chassis was 170v and L2 to chassis was was 70v and neutral to chassis was 50v. Don,t guess I will ever know,cannot get back to play with it.
icehouse Posted: Saturday, November 15, 2008 2:59:58 PM(UTC)
 
Fixed appliances on three-wire circuits

In the USA, the cases of some ovens and clothes dryers were grounded through their neutral wires, as a measure to conserve copper during the Second World War. This practice was removed from the NEC in the 1996 edition, but existing installations may still allow the case grounding of such appliances to be connected to the neutral conductor. Note that the NEC may be amended by local regulations in each state and city. This practice arose from the three wire system used to supply both 120 volt and 240 volt loads. Because ovens and dryers have components that use both 120 and 240 volts there is often some current on the neutral wire. This differs from the protective grounding wire, which only carries current under fault conditions. Using the neutral conductor for grounding the equipment enclosure was considered safe since the devices were permanently wired to the supply and so the neutral was unlikely to be broken without also breaking both supply conductors. Also, the unbalanced current due to lamps and small motors in the appliance was small compared to the rating of the conductors, and so unlikely to cause a large voltage drop in the neutral conductor.
denman Posted: Saturday, November 15, 2008 7:55:05 AM(UTC)
 
I am not focusing on the transformer but on the connection points which just happen to be at the transformer.

Why when connected to L1 and Neutral at the transformer do you see a low voltage when at other places in the unit you see the full 120 (L1 to N)?
Something very weird is happening. Finding out what that is may help troubleshoot.

You may even just be reading stray voltage. Get a 10 to 20 watt, 120 volt bulb, solder a couple wires to it and check from L1 to ground and L2 to ground. If she lights up it is real if not it is probably stray (volts but no real amps).

This is just safer than trying it with the amps setting and blowing a meter. Could also put a resistor in line with one of your meter leads to keep any current below the meter's max.

You said you disconnected the transformer, did you check L1 and L2 to ground with it disconnected re: P24-3 to P24-1?

I would also disconnect most plugs from the board, this should help eliminate any external causes, looks like the only one you need for power is P24
THIS FORUM IS DEAD!!!!!!!
Earl Dryer Posted: Saturday, November 15, 2008 5:39:04 AM(UTC)
 
Well folks, I don't know how all the attention got to the transformer, I know it is bad. I disconnected it and ohmed it, the secondary is open the primary showed some resistance (don't recall how much).
My original question was why do I have the correct voltages between line & neutral and a large difference between line and chassis ground. Neutral & Ground should be at the same potential.
icehouse Posted: Friday, November 14, 2008 6:45:48 AM(UTC)
 
Question ? Why not disconnect your transformer primary and wire it with a test cord? This will let you know that the transformer is good and that you have a problem in the wiring.
denman Posted: Thursday, November 13, 2008 6:13:04 PM(UTC)
 
It tells me that when you measure across the transformer primary you are not actually connected to L1 and Neutral but are most likely measuring L1 to chassis.

How this is happening, that is the big question!!!
Unfortunately the tech info does not give an actual electronics schematic.

I would conclude though that there has to be an open in the connection from the primary to either L1 or Neutral otherwise you would see the 120 volts at the primary.
THIS FORUM IS DEAD!!!!!!!
Earl Dryer Posted: Thursday, November 13, 2008 4:04:05 PM(UTC)
 
So,what does that tell you?
denman Posted: Thursday, November 13, 2008 5:57:52 AM(UTC)
 
My question was regarding this part of your post
"I have an open secondary but I only have 80v to primary so even with a good Xfmr my LV output is going to probably pretty low too."

But the Xfrm is not connected to ground. It is connected to L1 and Neutral so you should see the 120 volts across the primary.

So I am still confused.
THIS FORUM IS DEAD!!!!!!!
icehouse Posted: Thursday, November 13, 2008 4:50:36 AM(UTC)
 
Originally Posted by: Earl Dryer Go to Quoted Post
Yes, you are missing something, you did not read all of the post. I said that I had the low voltage to ground on L1 not L2 and the 2ndary winding was open. I do not know what the low voltage is supposed to be, I've been told 12-15v, 20vdc and I have personally measured 25vac on a similar oven. The point is there is 180v on L2 to ground & 70v on L1 to ground. The readings to neutral are 120 on each leg & 240 between them.
The primary could be shorted to ground.

You should re-read your post. You clearly state L2-ground 70vac. You have a short to ground period. And Whirlpools technical bulletin states "Primary" 120vac, "Secondary" 11.5 vac.
Earl Dryer Posted: Thursday, November 13, 2008 4:42:47 AM(UTC)
 
Yes, you are missing something, you did not read all of the post. I said that I had the low voltage to ground on L1 not L2 and the 2ndary winding was open. I do not know what the low voltage is supposed to be, I've been told 12-15v, 20vdc and I have personally measured 25vac on a simular oven. The point is there is 180v on L2 to ground & 70v on L1 to ground. The readings to neurtal are 120 on each leg & 240 between them.
The primary could be shorted to ground.