Can't Find a 20 or 25 Amp Auxiliary Switch for a TC45D

[grsthegreat]

the relay approach is the only way to go. Most all tractors (and truck/auto) use relays to control larger loads. Relays handle from a few amps to 200 amps, and are cheap.

easy to wire and easy to use.

 

[WCarp]

Now there you go. . . using your head and bringing practical good design into all of this.:thumbsup:

An attribute of good design is simplicity which affects cost and also the difficulty to implement it plus other factors.

With only one switch to directly control the current, there is only one switching device in the circuit. So only one needs to be purchased and then installed. A relay would increase the complexity to implement since two circuits need to be installed and of course the cost and finding one and then the time to mount it. A relay in this case would not significantly change the amount of heavy gauge wire needed.

The relay would also draw an additional small current from the system. On page 55-30 of New Holland's Service Manual, it lists 10 relays in the deluxe tractor. If the amperage used for all of the relays is totaled for the coils in all of the relays, a person might be surprised at the current used just to control the relays. It is good the think "green" and minimize additional loads on the system. Since I plan on having the device powered that I am adding to the tractor while the engine is not running for awhile, it is good to consider the elimination of unnecessary loads.

 

[Harry in Ky]

If you're that worried about a complicated system, why bother with a switch? Just use a jumper wire with an aligator clamp to the battery. You can even use a GREEN one.

 

[WCarp]

If you're that worried about a complicated system, why bother with a switch? Just use a jumper wire with an aligator clamp to the battery. You can even use a GREEN one.

That would not be practical and actually it would take two wires and the wire color is actually incorrect so it would be poor engineering design. You are obviously not familar with what I am attempting to do.

 

[jinman]

An attribute of good design is simplicity which affects cost and also the difficulty to implement it plus other factors.

With only one switch to directly control the current, there is only one switching device in the circuit. So only one needs to be purchased and then installed. A relay would increase the complexity to implement since two circuits need to be installed and of course the cost and finding one and then the time to mount it. A relay in this case would not significantly change the amount of heavy gauge wire needed.

The relay would also draw an additional small current from the system. On page 55-30 of New Holland's Service Manual, it lists 10 relays in the deluxe tractor. If the amperage used for all of the relays is totaled for the coils in all of the relays, a person might be surprised at the current used just to control the relays. It is good the think "green" and minimize additional loads on the system. Since I plan on having the device powered that I am adding to the tractor while the engine is not running for awhile, it is good to consider the elimination of unnecessary loads.

I didn't aim my comment at you, but rather to a gent who gave his best advice that is instantly recognizable as the perfect solution by anyone familiar with high current loads and especially inductive loads. Those are the kinds of people who designed your tractor. That's why flipping the headlight switch energizes a relay instead of powering the lights directly. That's why the glow plugs are powered by a relay instead of the ignition switch. Add to that list the turn signals, cruise control magnet, rabbit/turtle switching and the operator safety relay to round out the list. Your 20-25 amp directly switched load is very high current to control directly from a switch. If due to inductive load, that switch arcs and the contacts fry, you'll wish you had done it differently. . . or maybe not.

Do it anyway you want, but don't be critical of someone who gives you good sound advice and is far more familiar with your tractor than you are. Do you honestly want us to believe that all the relays in your tractor are energized all the time it is running? C'mon! We're trying to help. Nobody is insulting you or even saying anything bad about your design. We're just recognizing a superior way of doing a circuit if you are interested. Everybody here wants you to be successful. We are ALL on your side if you'll let us be on your team.

 

[aczlan]

That would not be practical and actually it would take two wires and the wire color is actually incorrect so it would be poor engineering design. You are obviously not familar with what I am attempting to do.

I don't think any of us are famillar with what you are doing as you haven't revealed that little tidbit to us.
As for relay power needed, IIRC, the relays I have used draw about 30mA. Not enough for me to worry about.

Aaron Z

 

[grsthegreat]

I just went thru a website dedicated to switches...and most are only rated at 5 amps continuous.

hate to say it, but there are reasons cars and trucks, etc use relays. the switches cant handle the loads.

 

[mkeith54]

I know this is an old subject, however for any current over 5 amps use a relay. locate the relay as close to the item being driven or the battery to shorten the run of heavy gauge wire, Also, always, repeat, always use a fuse on the battery side of the relay and the power side of the switch. yes it adds to the complexity of the circuit but it greatly reduces the chances of fire from a short circuit or bad wiring.