taurus fan, diode part #

[Skiddy]

[/topic]

I'm having a guy come over Sun to do the Al welding - even if I could borrow the equipment, I'm nowhere near good enough to try that.

i see what you mean, that's why they make grinders;D

 

[EBCRAWLR]

You can. Read this:
http://www.supermotors.net/forums/thid-5972-how-do-i-post-pictures-sounds-and-or-videos

yeah well.... %)

i would rather spend the 10 or 12 dollars or whatever it was and become a contributor!

 

[Steve83]

You can contribute and upload pics either way. Uploading them that way puts less load on the CB server, which reduces Jon's costs, so your contribution goes farther.

 

[EBCRAWLR]

sorry for the wait, but for those that were interested.. skiddy has the pic to upload. let me know if u have and questions regarding the schematic?

thanks again skiddy

 

[Skiddy]

sorry for the wait, but for those that were interested.. skiddy has the pic to upload. let me know if u have and questions regarding the schematic?

thanks again skiddy

here you go no problem

 

[DanWheeler]

question - why are you running +12v through the NC terminal on the high speed relay over to the low speed relay? If your high speed relay fails, fuse blows or the contacts get corroded inside the relay it will cause a downstream failure on the low speed relay.

might be good to add some redundancy there

Seems like it should work fine though

 

[EBCRAWLR]

redundancy would be bad at that point. and here was my issue...

because it is controlled by a temp switch, once the low speed, coil side of the relay is open, the low speed would be activated. NOW when the high side kicks on, it takes the 12 volts away from the low side control, even though coil is still open, and puts it to the high side. if redundancy was in place (12v fused to low speed control, is constant) it would have 12v in both high and low speeds! which i think played a part in my initial failure.

idk.... i still dont run with my low speed connected at the moment because i have things going on (life), but in the next week or two, im gonna re-connect the low side and see if i blow anything. (whether it be the fan, or a relay/ fuse) (im still concerned about the fan generating voltage to low circuit)

as of now with just high speed, everything is working perfectly! cycles on at 200, and off at 180.

 

[EBCRAWLR]

If your high speed relay fails, fuse blows or the contacts get corroded inside the relay it will cause a downstream failure on the low speed relay.

very true! i run a 65 amp manually resettable circuit breaker, so that would pop first and say hey dummy something is wrong here! BUT i do carry spare 80 and 40 amp relays and a circuit breaker on the trail.

 

[DanWheeler]

According to your wiring diagram, the high and low speed can't be on at the same time because both relays are controlled by a switch that can't energize both relays at the same time. Only one at a time. High or Auto. Never both simultaneously.

 

[EBCRAWLR]

very true! which is why 12volts direct to the low side would be bad.
the high relay switches the power.

 

[EBCRAWLR]

i think i know what ur saying now! take a look at the schematic again... (idk why its turned...) but in both high and auto, 12volts is applied to the coil side of the relay. (i drew the connection at the high relay coil side.

 

[DanWheeler]

Wait a second, why are the positive inputs to your 2 relays tied together?

That would cause both relays to be energized at the same time all the time... but since you are running the low speed relay through the NC circuit of the high speed relay, that would prevent them from running simultaneously.

however, that would mean when you have your switch set to auto, power would be supplied through the hi-speed relay to the fan, but the low-speed relay circuit would be CLOSED when above 180 which would allow voltage to flow backwards through the system.

so... yeah, there's your problem. Makes sense now I think. You ARE backfeeding voltage.

You need to simplify your wiring. Just separate them out into 2 completely separate circuits. Your On/Off/Auto switch will prevent the relays from being on simultaneously.

 

[DanWheeler]

oh I didn't see your most recent post until just now but yeah I think we're on the same page now.

 

[Bronchole]

Your schematic looks fine to me. When the fan is running in high mode the low back EMF (I think that is the technical term for the voltage coming back on the low speed windings) goes back in to the low speed relay and because it is probably that the low speed relay is active at this point the voltage travels back over to the NC contact of the high speed relay where it does nothing because the high speed relay is active and is closed on to the NO contact. I say you are good to go.

I get the idea that this is not the way the fan that burned up was connected. Can we get a schematic on that? Maybe there was something wrong there.

 

[DanWheeler]

Your schematic looks fine to me. When the fan is running in high mode the low back EMF (I think that is the technical term for the voltage coming back on the low speed windings) goes back in to the low speed relay and because it is probably that the low speed relay is active at this point the voltage travels back over to the NC contact of the high speed relay where it does nothing because the high speed relay is active and is closed on to the NO contact. I say you are good to go.

I get the idea that this is not the way the fan that burned up was connected. Can we get a schematic on that? Maybe there was something wrong there.

oh... yeah, you're right. I spoke to soon. The backfed voltage would be dead ending at the high speed relay.

nevermind!

 

[Bronchole]

It's fine the way he has it.

auto mode:
Both relays get + to the coils from the auto/off/on switch. The ground to the coils is provided by the thermal switch for each relay. When it is below 180° both + leads to the fan are open. When it is above 180°, but below 200° the 12 AWG low fan lead gets power thru the NO contact of the low relay which gets its power from the NC contact of the high relay which gets its power from the fused lead to the battery. at 200° the high relay opens its NC contact which removes power going to the low relay and closes on to the 10 AWG high speed. Both relays are active, but the wire coming from the low speed is left open.

Off mode:
There is no positive power being ran to the coils of both relays so neither of them can be activated. This wil have the relays in the positions shown on the schematic. Both leads from the fan are left unconnected to any power.

On mode:
Both relay coils are getting positive from the auto/off/on switch. The high relay is also getting ground from the auto/off/on switch. This make the high relay colse to the NO contacts and sends power to the 10 AWG high fan. No power is sent to the low relay so weather it is closed or open the 12 AWG low fan lead is not hooked up to any power, it is the same as a dangling wire.

All is good, you are good for throttle up.

 

[DanWheeler]

agreed, it should work as-is. I do think its a bit overcomplicated and prone to failure by intertwining the high and low. Below is how I have mine set up. If one circuit fails due to fuse or relay, the other circuit will continue to work.

 

[Bronchole]

The downside to yours is that it doesn't have the second thermostatic switch that automatically kicks in if the temp exceed 200°. I know you do not think you need that, but it is a feature I can appreciate of the other setup.

You also do not have an off position. In my mind that is an advantage. I understand the need to be able to dissable the fan for deep water crossings. I have had an off position on some of my previous setups and I have to say the convienience of having the off position is far outweighed by the possibility of accidently having the fan off and overheating. Personally I will not do an off switch again. It's too simple for the once or twice a year I need to dissable the fan to just simply pull the fuse. To each his own though.

 

[Bronchole]

BTW Skiddy, what part number relays are you using? What part number thermal switches and how are they installed?

I have been kicking around the idea of tapping a thermostat housing to use one on the dual output thermal switches, but haven't got to the point of buying the switch and tap yet.

 

[DanWheeler]

The downside to yours is that it doesn't have the second thermostatic switch that automatically kicks in if the temp exceed 200°. I know you do not think you need that, but it is a feature I can appreciate of the other setup.

You also do not have an off position. In my mind that is an advantage. I understand the need to be able to dissable the fan for deep water crossings. I have had an off position on some of my previous setups and I have to say the convienience of having the off position is far outweighed by the possibility of accidently having the fan off and overheating. Personally I will not do an off switch again. It's too simple for the once or twice a year I need to dissable the fan to just simply pull the fuse. To each his own though.

I guess it's not apparent in my drawing but the switch is a 3 position so the middle position would be OFF.

I didn't see the 200 degree thermal switch. Thats a good idea. I am out of places to put thermal switches. I tapped the thermostat housing already.

The drawing doesn't show it but I am actually using a Derale adjustable fan controller for the low speed/auto mode.

Also not shown in the drawing is a circuit I added to send +12v to a piezo alarm when the switch is in the off position. Basically, the auto and high positions on the switch power a relay which has the piezo connected the NC terminal so it alarms when the fan is set to OFF.

That way I don't forget to turn the fan back on after a stream crossing.