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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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#1
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Ammeter - which way
Remember the old type charge / discharge ammeters, where used a couple
of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
#2
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Ammeter - which way
Harry Bloomfield wrote:
Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? My Lard Roller ammeter is marked - to the left, + to the right, as have all the others I've used. Has your tractor mower been converted from +ve to -ve earth at some point? -- Tciao for Now! John. |
#3
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Ammeter - which way
John Williamson presented the following explanation :
Harry Bloomfield wrote: Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? My Lard Roller ammeter is marked - to the left, + to the right, as have all the others I've used. Has your tractor mower been converted from +ve to -ve earth at some point? No, it is not that old - I suspect the coil windings (2 turns) were simply fitted the wrong way and it has bothered me since I got it. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
#4
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Ammeter - which way
Harry Bloomfield wrote:
John Williamson presented the following explanation : Harry Bloomfield wrote: Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? My Lard Roller ammeter is marked - to the left, + to the right, as have all the others I've used. Has your tractor mower been converted from +ve to -ve earth at some point? No, it is not that old - I suspect the coil windings (2 turns) were simply fitted the wrong way and it has bothered me since I got it. Is it fitted upside down? Bill |
#5
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Ammeter - which way
After serious thinking Bill Wright wrote :
Harry Bloomfield wrote: John Williamson presented the following explanation : Harry Bloomfield wrote: Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? My Lard Roller ammeter is marked - to the left, + to the right, as have all the others I've used. Has your tractor mower been converted from +ve to -ve earth at some point? No, it is not that old - I suspect the coil windings (2 turns) were simply fitted the wrong way and it has bothered me since I got it. Is it fitted upside down? Bill No, someone had wound it the wrong way when the tractor was built :-? It uses a couple of turns of the main wire feed, wrapped around a metal bracket at the back of the meter and the wire had a sticky label on it showing the direction of flow. I have rewound it so it reads charge with needle moving to the right. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
#6
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Ammeter - which way
On Wed, 29 May 2013 17:55:58 +0100, Harry Bloomfield
wrote: After serious thinking Bill Wright wrote : Harry Bloomfield wrote: John Williamson presented the following explanation : Harry Bloomfield wrote: Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? My Lard Roller ammeter is marked - to the left, + to the right, as have all the others I've used. Has your tractor mower been converted from +ve to -ve earth at some point? No, it is not that old - I suspect the coil windings (2 turns) were simply fitted the wrong way and it has bothered me since I got it. Is it fitted upside down? Bill No, someone had wound it the wrong way when the tractor was built :-? It uses a couple of turns of the main wire feed, wrapped around a metal bracket at the back of the meter and the wire had a sticky label on it showing the direction of flow. I have rewound it so it reads charge with needle moving to the right. Does it matter? As long as *you* know which way is charging. -- Graham. %Profound_observation% |
#7
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Ammeter - which way
On 29/05/2013 15:18, Bill Wright wrote:
Harry Bloomfield wrote: John Williamson presented the following explanation : Harry Bloomfield wrote: Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? My Lard Roller ammeter is marked - to the left, + to the right, as have all the others I've used. Has your tractor mower been converted from +ve to -ve earth at some point? No, it is not that old - I suspect the coil windings (2 turns) were simply fitted the wrong way and it has bothered me since I got it. Is it fitted upside down? Bill if you don't like the way it goes just reverse the wires |
#8
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Ammeter - which way
On Wednesday, May 29, 2013 1:09:14 PM UTC+1, Harry Bloomfield wrote:
Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? I think you're right, but you can have it how you like |
#9
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Ammeter - which way
On Wed, 29 May 2013 13:09:14 +0100, Harry Bloomfield
wrote: Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? Fleming’s Left Hand Rule http://www.le.ac.uk/se/centres/sci/selfstudy/mam12.htm Oh wait, maybe it's the right hand rule http://physicsed.buffalostate.edu/Se...ce/rhr/rhr.htm hth ;-) -- Graham. %Profound_observation% |
#10
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Ammeter - which way
"Harry Bloomfield" wrote:
Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? The usual orientation for a charge/discharge ammeter is with the quiescent needle pointer resting at 12 O'clock (needle pivot at 6 O'clock); the negative (-) discharge sector to the left (anticlockwise) and the positive (+) charging sector to the right (clockwise). Some ammeters (like yours) rather unhelpfully are not marked + and -. However, they are usually colour-coded (blue or green sector for charging; red sector for discharging), or annotated 'Charge' and 'Discharge' or simply 'C' and 'D'. Doesn't your ammeter have any of these legends or markings? There are some versions of these ammeters designed to be mounted the other way up, with the quiescent needle pointer resting at 6 O'clock. If your ammeter is actually mounted upside-down (as has already been suggested), then the needle would appear to read the wrong way. However, there must be some lettering on your ammeter ('Amps' or 'A', or the manufacturer's name) that would be inverted if the ammeter has been mounted the wrong way up. When you say, "The needle goes left when on charge...", is that when charging from an external battery charger, or when charging from an engine mounted alternator? If the latter, then your alternator could be faulty and not generating enough output to meet demand. Check the wiring diagram (if you have one!) to see where in the circuit the ammeter has been located. Also check the ammeter connections to see if it has been connected reverse polarity. -- Interloper |
#11
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Ammeter - which way
After serious thinking Interloper wrote :
"Harry Bloomfield" wrote: Remember the old type charge / discharge ammeters, where used a couple of turns of cable which used to sometime be fitted to vehicles ? I have one fitted to the tractor mower which is not marked + and - and I'm sure it reads the wrong way. The needle goes left when on charge, I seem to remember the norm is to move to the right. Can anyone remember, before I take steps to correct it? The usual orientation for a charge/discharge ammeter is with the quiescent needle pointer resting at 12 O'clock (needle pivot at 6 O'clock); the negative (-) discharge sector to the left (anticlockwise) and the positive (+) charging sector to the right (clockwise). Some ammeters (like yours) rather unhelpfully are not marked + and -. However, they are usually colour-coded (blue or green sector for charging; red sector for discharging), or annotated 'Charge' and 'Discharge' or simply 'C' and 'D'. Doesn't your ammeter have any of these legends or markings? There are some versions of these ammeters designed to be mounted the other way up, with the quiescent needle pointer resting at 6 O'clock. If your ammeter is actually mounted upside-down (as has already been suggested), then the needle would appear to read the wrong way. However, there must be some lettering on your ammeter ('Amps' or 'A', or the manufacturer's name) that would be inverted if the ammeter has been mounted the wrong way up. This one has the pivot at the bottom and points to 12. There are no markings apart from 30 amp at either end and a 15amp marker. It kicks left slightly (or did) when the starter solenoid engaged, then with the engine running, would show around 5amps. No marks to indicate which side was which at all. When you say, "The needle goes left when on charge...", is that when charging from an external battery charger, or when charging from an engine mounted alternator? If the latter, then your alternator could be faulty and not generating enough output to meet demand. No, when the engine is running it went to the left - which seemed wrong to me. Check the wiring diagram (if you have one!) to see where in the circuit the ammeter has been located. Also check the ammeter connections to see if it has been connected reverse polarity. Its in series with everything, apart from the starter main feed - just the ignition circuit the interlocks and alternator really. The lights rather oddly, are run from a separate output of the alternator. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
#12
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Ammeter - which way
snip
It kicks left slightly (or did) when the starter solenoid engaged, then with the engine running, would show around 5amps. No marks to indicate which side was which at all. When you say, "The needle goes left when on charge...", is that when charging from an external battery charger, or when charging from an engine mounted alternator? If the latter, then your alternator could be faulty and not generating enough output to meet demand. No, when the engine is running it went to the left - which seemed wrong to me. But you also say that it deflected left when the solenoid engaged, which would be correct for a left-side discharge indication, as the solenoid would be drawing current - i.e. discharging the battery - at this time, as the engine would not be running, and the alternator would not be attempting to charge the battery. On cars that I have owned that have had an ammeter fitted, the usual sequence of events would be a small deflection to the left as the ignition was switched on, followed by a much larger deflection to the left when the solenoid pulled in for starting, followed by a jump to the right of 10 or more amps once the engine was running, fairly quickly dropping back to 2 to 5 amps maintenance charge. All seems very odd, if you ask me ... :-| Arfa |
#13
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Ammeter - which way
Arfa Daily was thinking very hard :
snip It kicks left slightly (or did) when the starter solenoid engaged, then with the engine running, would show around 5amps. No marks to indicate which side was which at all. When you say, "The needle goes left when on charge...", is that when charging from an external battery charger, or when charging from an engine mounted alternator? If the latter, then your alternator could be faulty and not generating enough output to meet demand. No, when the engine is running it went to the left - which seemed wrong to me. But you also say that it deflected left when the solenoid engaged, which would be correct for a left-side discharge indication, as the solenoid would be drawing current - i.e. discharging the battery - at this time, as the engine would not be running, and the alternator would not be attempting to charge the battery. On cars that I have owned that have had an ammeter fitted, the usual sequence of events would be a small deflection to the left as the ignition was switched on, followed by a much larger deflection to the left when the solenoid pulled in for starting, followed by a jump to the right of 10 or more amps once the engine was running, fairly quickly dropping back to 2 to 5 amps maintenance charge. All seems very odd, if you ask me ... :-| Arfa Sorry - now kicks to the left as the solenoid is engaged. Previously it kicked to the right. -- Regards, Harry (M1BYT) (L) http://www.ukradioamateur.co.uk |
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