SimonPearson Posted February 25, 2006 Share Posted February 25, 2006 OK, I admit I'm hopeless with electrics.... What does a relay do, and why do you need one in a circuit in, for example, an electric fan? Quote Link to comment Share on other sites More sharing options...
minivin Posted February 25, 2006 Share Posted February 25, 2006 OK, I admit I'm hopeless with electrics.... What does a relay do, and why do you need one in a circuit in, for example, an electric fan? a relay is used to control one circuit, by an easier means. This can either be in the form of a 12VDC switched relay controlling a 240Vac line, or a 12VDC low current switching line, controlling a 12VDC high current line, such as spot lamps et cetera. So, to summarize, for the control of circuits that may need mahoosive switches to cope with high currents or high voltages, the relay is put in place so that a ickle switch may then control those circuits Quote Link to comment Share on other sites More sharing options...
Les Henson Posted February 25, 2006 Share Posted February 25, 2006 You need a relay to switch a heavier current from another source, such as directly from the battery - to power high ampage items, such as winch, spot lamps, electric fan, etc. You use existing wiring to supply power to activate the solenoid, which then takes power directly from the battery (usually) and supplies it to whatever you have fitted. Some people think that a relay fitted means you don't need a fuse, but that's not the case. The circuit still needs overload protection. Fans have a higher ampage to start than they do to run, so the fan may need (for instance) 25-amps to start, but then 15 to stay running. Les. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted February 25, 2006 Share Posted February 25, 2006 <Irritating Geordie Big Brother Commentary Voice> 10:03 am. Les earns himself ten minutes in the electrical dunce corner for using the word "Ampage". His task for the day is to sit and write out "current" five hundred times. <IGBBCV> Quote Link to comment Share on other sites More sharing options...
Guilford Dave Posted February 25, 2006 Share Posted February 25, 2006 OK, I admit I'm hopeless with electrics.... What does a relay do, and why do you need one in a circuit in, for example, an electric fan? Simon, Nice easy explaination here. www.bcae1.com/relays.htm Dave Quote Link to comment Share on other sites More sharing options...
Les Henson Posted February 25, 2006 Share Posted February 25, 2006 current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.curren t.current.current.current.current.current.current.current.current.current.curren .current.current.current.curre nt.current.current.current.current.current.current.current.current.current.curre t.current.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. Satisfied? Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted February 25, 2006 Share Posted February 25, 2006 ROFL Quote Link to comment Share on other sites More sharing options...
GBMUD Posted February 25, 2006 Share Posted February 25, 2006 current.current.current.current.current.current.current.current.current.current.urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.curren t.current.current.current.current.current.current.current.current.current.curren .current.current.current.curre nt.current.current.current.current.current.current.current.current.current.curre t.current.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. urrent.current.current.current. current.current.current.current.current.current.current.current.current.current. Satisfied? Raisin. Chris Quote Link to comment Share on other sites More sharing options...
s2hotdog Posted February 25, 2006 Share Posted February 25, 2006 Simon I'm the same I have 2 fans on my D90 one for the intercooler other for the rad When I first put them on wired through cigarett lighter circuit .............. me thinks easy no probs Needless to say kept blowing fuses so sought advice from an auto sparky and here So rewired directly from battery to 2 switches and 2 relays with in line fuses......... No probs now fans work a treat As I said I'm carp at electrics but that worked for me and not the best at explaning over this medium Hope this helps Cheers Steve Quote Link to comment Share on other sites More sharing options...
Tom P Posted February 25, 2006 Share Posted February 25, 2006 Its for safty, its better to have small V/I running though the swich rather than a large V/I Tom Quote Link to comment Share on other sites More sharing options...
minivin Posted February 25, 2006 Share Posted February 25, 2006 Its for safty, its better to have small V/I running though the swich rather than a large V/I Tom Voltage divide by current is resistance do you mean power, or a ratio? Quote Link to comment Share on other sites More sharing options...
Bill Wright Posted February 26, 2006 Share Posted February 26, 2006 Voltage divide by current is resistance do you mean power, or a ratio? OHMS Law isn't it. V I R where V = voltage, I = amperage and R = Resistance. The formula looks like this __V___ I x R Voltage = Amperage x Resistance Amperage = Voltage / Resistance Resistance = Voltage / Amperage Useless bit of info Bill Wright Quote Link to comment Share on other sites More sharing options...
Tom P Posted February 26, 2006 Share Posted February 26, 2006 I meant a high voltage or current, I thought it would have saved me some time obviously not lol Trust you lot to nit pick lol Tom Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.