Tell me about Relays

bob 6600

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I'm not to hot on relays and electrical stuff (still learning!) so would appreciate some help. Not on an MB but I have a fuel pump relay that needs replacing on an old Ford. The Relay is as in the picture below. Now, I have searched may sites and even ebay but cannot find one that matches the diagram on the back. It could be that it's an old diagram and there are newer ones that are identical but I cannot be sure. If anyone could point me to an identical replacement I would be grateful. I think it's known as a 'normally open' relay

ACtC-3djIjwsnhkBVw3IJc6v2tlEJkIxoFQQSA38w1YTLJlpyyiAPfTlH96GOXBtxylut-MDvn9sQAIbTAC9B2FckIIwMib4fC446DPUeCsj_Ly2R1z179ZRTmCJlIrcFAy_4I6ccBqE1aVF-CQh28T32IzZiw=w678-h903-no
 

Tony Dyson

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Search for 10R 02 7025- relay 27 and you will find options, you would need to ensure you sourced the same pin configuration as existing.

It is a single pole, single throw, NO 12VDC 40A Control relay.
 

mioba

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Go to your ford dealer with the vin. You wont be guessing.
 
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bob 6600

bob 6600

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Go to your ford dealer with the vin. You wont be guessing.
It has been rewired and has an uprated fuel pump so I don't think that will work. It's for a Cossie and having searched on Ford forums, there doesn't seem to be a definitive answer.
 
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bob 6600

bob 6600

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This is the sort of thing that comes up time and time again. The diagram is slightly different but are they the same thing? I know the 85 and 86 are on opposite pins but I think I've seen one the right way around

s-l1600.jpg
 

EmilysDad

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This is the sort of thing that comes up time and time again. The diagram is slightly different but are they the same thing? I know the 85 and 86 are on opposite pins but I think I've seen one the right way around

s-l1600.jpg
That relay will be perfect. The 85 & 86 contacts are for the low current trigger/switch supply. Pin 30 is for the supply for the up to 40 amps, but on this relay there are Normally Open contacts 87 and Normally Closed 87a ... you'd just use the 87 contact.
You'll find some relays also have two 87 contacts that you might use to wire a pair of spot lights so that each spot light uses a single connection .... you'd be able to use one of them too (being careful that when energised if you only use one of the two connections, the other will also be live so would have to be insulated)

PS I stand to be corrected, but I think that the relay you're holding has 87 twice because it has a fuse incorporated within the relay. The other relays shown, would need to be fused separately.
 

Tony Dyson

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Pins 87 and 30 are the NO contacts in your old relay
Pins 87 and 30 are the NO contacts in your new relay

All you need to ensure is that the pin locations between your two relays are aligned and the new will perform the same as your old.

@EmilysDad 87 appears twice in the old relay as it will be a standard pattern base to provide for a NC contact (missing) not a fuse.
 

Tony Dyson

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This is the sort of thing that comes up time and time again. The diagram is slightly different but are they the same thing? I know the 85 and 86 are on opposite pins but I think I've seen one the right way around

s-l1600.jpg
Pins 85 and 86 feed the coil, so it makes no difference which way round it is fed.
 

Wearsafoxhat

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Yup, all good info above.
Just to add, the diagram on the relay are for it in its de-energised state, not switched on, no supply to the coil so a circuit connected across 30 and 87a (N/C) would be on, then switched off when the relay is energised.
The supply on pin 30 would be switched to 87 (N/O) and turn that circuit on..

spent some time as an instructor, old telephone exchanges, relays and basic electronics.


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Wearsafoxhat

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Things have moved on a little since .... ;)

They certainly have, I’ll not mention valves then

but have found many electrical engineers still struggle with a basic relay circuit, but can do wonders with things I can’t see, ip, port forwarding or even ordering things from Wickes


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Blobcat

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They certainly have, I’ll not mention valves then

but have found many electrical engineers still struggle with a basic relay circuit, but can do wonders with things I can’t see, ip, port forwarding or even ordering things from Wickes


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Who doesn’t like a nice strowger two motion selector ;) :p
 

Wearsafoxhat

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Who doesn’t like a nice strowger two motion selector ;) :p

Finicky ole things them... lift handset, A relay energises, dial tone sent, uniselector finds next available line ... still have the contact cleaning and straightening bits somewhere


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Blobcat

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Finicky ole things them... lift handset, A relay energises, dial tone sent, uniselector finds next available line ... still have the contact cleaning and straightening bits somewhere


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Cleaned and setup a few of them on board ships, not the most pleasant of tasks (That and emergency battery maintenance)
 
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bob 6600

bob 6600

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This seems to be the only one I can find and it comes in a pack of 10. The 'similar to Bosch' number is an old one. Frustratingly Bosch's catalogue only has 30a variants in their catalogue


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bob 6600

bob 6600

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This seems to be the only one I can find and it comes in a pack of 10. The 'similar to Bosch' number is an old one. Frustratingly Bosch's catalogue only has 30a variants in their catalogue


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Thank you to everyone who replied to this thread, I now know a (little) more about relays! To close this off, I ordered these and the car started on the first turn of the key!
 


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