12V DC Relay Issues (Diesel Engine) | Page 3 | on ElectriciansForums

12V DC Relay Issues (Diesel Engine)

Post new thread

Discuss 12V DC Relay Issues (Diesel Engine) in the UK Electrical Forum area at ElectriciansForums.net

H

Holden Customs

-
DIY
Joined
Jun 26, 2019
Messages
22
Reaction score
7
Location
Vancouver, Canada
Hello all. I am having an issue with a 12V DC Relay I am trying to install to run a kill switch on a John Deere Diesel engine that runs a high pressure water pump. I have the relay wired in such that it will send power to the ignition when an electrical signal comes from a water sensor in the pump (dry running protection). The issue I have is that whenever it is hooked up all I get is chatter from the relay. I have tested my wiring by connecting the "switch" wire to battery and everything works as it should. I read somewhere that if the switch voltage is less than the feed that it can cause chatter. The fees voltage is 12.56 and the switch voltage is 12.22. Could this be the reason and how should I go about fixing it? Thanks
 

Attachments

  • [ElectriciansForums.net] 12V DC Relay Issues (Diesel Engine)
    15615585866361309218059.jpg
    970.8 KB · Views: 46
Sort by date Sort by votes
Please could you post a link to the specific sensor, so that we know exactly what kind of output it has and how it responds. I'll post a suggested circuit to convert its signal into a relay drive voltage.
 
Upvote 0 Downvote
Lucien Nunes said:
Please could you post a link to the specific sensor, so that we know exactly what kind of output it has and how it responds. I'll post a suggested circuit to convert its signal into a relay drive voltage.
Click to expand...

Now that is an offer you can't refuse @Holden Customs
 
Upvote 0 Downvote
Lucien Nunes said:
Please could you post a link to the specific sensor, so that we know exactly what kind of output it has and how it responds. I'll post a suggested circuit to convert its signal into a relay drive voltage.
Click to expand...
Hey thanks for the offer. I have attached a data sheet of the sensor. It is a Baumer Clever Level LBFI.
 

Attachments

  • Baumer_LBFI_EN_20190513_DS.pdf
    2.9 MB · Views: 26
Upvote 0 Downvote
Looks like that sensor should give a definite logic output, and it has hysteresis which should prevent any 'chattering'. Unless the hysteresis gap is too small maybe.
 
Upvote 0 Downvote
Is the circuit such as when the sensor is active, it energises the relay which in turn kills the ignition circuit that is feeding the sensor, creating a feedback loop resulting in a constant chatter?
 
Upvote 0 Downvote
James the Spark1976 said:
Is the circuit such as when the sensor is active, it energises the relay which in turn kills the ignition circuit that is feeding the sensor, creating a feedback loop resulting in a constant chatter?
Click to expand...
It is the opposite. As when the sensor is active it energizes the relay which in turn energizes the ignition.
 
Upvote 0 Downvote
Last edited:
Upvote 0 Downvote
Or just a link to the type of relay. The point here is that the different models of sensor have different output circuits; one requires the relay coil return to positive, one requires it to go to negative, one probably doesn't matter. The sensor's 100mA output current rating is sufficient to drive some relays but not all; yours may well be presenting it with a borderline overload and triggering its output protection if the coil resistance is too low.

Re wiring, no, the cable size is more or less immaterial at these low currents, any normal cable physically strong enough to use will be ample for the sensor circuit unless it's tens of metres long.
 
Last edited:
Upvote 0 Downvote
Lucien Nunes said:
Or just a link to the type of relay. The point here is that the different models of sensor have different output circuits; one requires the relay coil return to positive, one requires it to go to negative, one probably doesn't matter. The sensor's 100mA output current rating is sufficient to drive some relays but not all; yours may well be presenting it with a borderline overload and triggering its output protection if the coil resistance is too low.

Re wiring, no, the cable size is more or less immaterial at these low currents, any normal cable physically strong enough to use will be ample for the sensor circuit unless it's tens of metres long.
Click to expand...
Hello. I wont be able to get the full type number of the sensor for about 3 weeks as it is on our machine at another spot in the country. As for the relay I am using it is this one attached. I think I am starting to see what you are saying. Thanks for the help.
 

Attachments

  • [ElectriciansForums.net] 12V DC Relay Issues (Diesel Engine)
    Pico Relay.PNG
    115.9 KB · Views: 16
Upvote 0 Downvote
I have tried a number of searches using the pico relay information but been unable to find out its coil resistance. Could you measure it or measure the current flowing through it at 12V? Then Lucien Nunes will have the information he needs on it.

:)
 
Upvote 0 Downvote
Re #43; Good idea but I don't think the one you pointed to is suitable because it is designed for ac switching applications, the minimum mains voltage from spec is 24V and it is a zero-crossing device so will need a sinusiod main power input to trigger the conduction of the thyristors. It relies on the ac current regularly being zero to turn off when the dc control voltage is removed.

A transistor or another relay is probably a better bet. We will have to wait for Dr Nunes...
 
Last edited:
Upvote 0 Downvote

Reply to 12V DC Relay Issues (Diesel Engine) in the UK Electrical Forum area at ElectriciansForums.net

Similar threads

L
UK Switching relay
I'm just trying to understand the current your suggested relay needs to handle. Surely the above is not the running current of the lamp? That...
Replies
2
Views
213
Avo Mk8
Avo Mk8
P
  • Question
Relay Design and Wiring
This contactor you suggested unfortunately only has two NO switches rather than 1 NC and 1 NO required for the CR3 current sensing bypass...
Replies
14
Views
1K
paulgill28
P

OFFICIAL SPONSORS

Electrical Goods - Electrical Tools - Brand Names Electrician Courses Green Electrical Goods PCB Way Electrical Goods - Electrical Tools - Brand Names Pushfit Wire Connectors Electric Underfloor Heating Electrician Courses
These Official Forum Sponsors May Provide Discounts to Regular Forum Members - If you would like to sponsor us then CLICK HERE and post a thread with who you are, and we'll send you some stats etc

YOUR Unread Posts

This website was designed, optimised and is hosted by untold.media Operating under the name Untold Media since 2001.
Back
Top