Switch Rules Question...

[Lacy Lodmell]

Hey folks,

We were just ordering electrical supplies today, and butted heads with the rules on switch type. The official rules state that the switch located above the shoulder must be of the "rotary type." This doesn't make much sense to me, as most rotary switches have many poles and are for selecting multiple settings (like on heater fan switches in cars). We were planning to use toggle switches; does anyone have some insight into this one? Thanks...

Lacy Lodmell
University of Idaho FSAE

[Lacy Lodmell]

Hey folks,

We were just ordering electrical supplies today, and butted heads with the rules on switch type. The official rules state that the switch located above the shoulder must be of the "rotary type." This doesn't make much sense to me, as most rotary switches have many poles and are for selecting multiple settings (like on heater fan switches in cars). We were planning to use toggle switches; does anyone have some insight into this one? Thanks...

Lacy Lodmell
University of Idaho FSAE

[Dominic Venieri]

go to http://www.delcity.net/control.html, then go to battery switches. They mean the "Battery Master Switch" by the rotating type switch. You can also get switches like that from Digikey, Jeg's, Truechoice, Pegasus,...

www.formularpi.com (http://www.formularpi.com)

[srikanth chilivery]

Hi Dominic Venieri,
I am too facing the same problem. please help as the link you provided is no more.

[shark.ashwa]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by srikanth chilivery:
Hi Dominic Venieri,
I am too facing the same problem. please help as the link you provided is no more. </div></BLOCKQUOTE>

Hi,

I think you will find this useful.
https://www.pegasusautoracing....tails.asp?RecID=1465 (https://www.pegasusautoracing.com/productdetails.asp?RecID=1465)

Regards,
Sharath

[TMichaels]

This seems to be a 2-pole switch which should not do it. You need a 4-pole switch, if the respective rule is enforced at scrutineering.

Regards,

Tobias

[Michael Royce]

Lacy,
There is a picture of the sort of switch you need on page 51 of the FSAE Rules!!! We put it there for a reason!

Tobias is correct. Depending on what alternator/generator you will be using, the 2 terminal switch referenced by Sharath may not shut off the engine at higher engine speeds. The note under B.11.1.2 points this out. You may need the one that also cuts the field circuit. That is the one pictured in the Rules. In addition to the 2 big terminals (for the battery lead), it has 4 smaller spade terminals. It can be purchased from Pegasus at:
https://www.pegasusautoracing....tails.asp?RecID=1464 (https://www.pegasusautoracing.com/productdetails.asp?RecID=1464)

[shark.ashwa]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:
This seems to be a 2-pole switch which should not do it. You need a 4-pole switch, if the respective rule is enforced at scrutineering.

Regards,

Tobias </div></BLOCKQUOTE>

Oops sorry!
Not an electrical guy, but I remembered seeing something like that on our car.
Anyway, the 4 pole switch that you spoke of is also I'm sure available at Pegasus!

Regards,
Sharath

[Nicky]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">This seems to be a 2-pole switch which should not do it. You need a 4-pole switch, if the respective rule is enforced at scrutineering. </div></BLOCKQUOTE>

We've been using the same 2-pole switch. However, how you connect it decides the functionality of the switch. We connect the output of the rectifier and positive of the battery to one of the terminals. While the positive of all the loads on the car are connected to the other terminal.

This way, all positive supply to the loads are disconnected on turning the switch off. The power supplied from the rectifier when the engine is turning off is directed into the battery.

Hope the intent of the rule is still satisfied...

[srikanth chilivery]

Hello Michael Royce,

I found it very useful.
But my doubt is that in the installation document provided by them, I see that the electrical power from the battery is connected to the thicker terminal. But I think that that will be used for mounting the switch.

Please help me if the installation diagram provided in their document is right or not.
If it is wrong then please help again....

[TMichaels]

Srikanth,
frankly speaking: Be an engineer and find out how to do it on your own as it is really obvious.

[Jon Burford]

Agree with TMichaels
Installation of the switch is not difficult. There will be heavy terminals for the large current and small terminals for the smaller current. there will probably also be mounting points.
If in doubt get the volt meter out.

[srikanth chilivery]

I have searched the local markets for the switches needed but I found this type of switches:

The master switch (https://picasaweb.google.com/lh/photo/Pn-LGmLkk1zSBgFaF_0U5tMTjNZETYmyPJy0liipFm0?feat=dire ctlink)

The cockpit master switch (https://picasaweb.google.com/lh/photo/zhHS4re4tgFIjFdpRMuoYtMTjNZETYmyPJy0liipFm0?feat=d irectlink)

I am confirm that the cockpit master switch is the same as shown with four poles.

I have doubt with the master switch( regarding the design). the switch is as per the rules (have 6 posts and on and off positions)

[Jon Burford]

I would not use a switch like you have chosen for the master switch, think about the current needed to be switched? try searching a motorsport supplier for the correct switch or make a google search.
The cockpit master switch is less important, as long as it is compliant with the rules virtually any switch will be okay.

[srikanth chilivery]

The switches I pasted above are industrial switches and are available in current ratings ranging from 50Amps to 500Amps. These switches are available spare in our college's workshop and have the rating of 180Amps( both the master and cockpit switches). I want to know If i can use them.

[Kirk Feldkamp]

Why don't you just measure it? We can't tell you how much juice your starting system will use... because we don't know! http://fsae.com/groupee_common/emoticons/icon_smile.gif

[TMichaels]

I would ask the rules committee of the respective event, if they will accept this kind of switch. I doubt it.

They do not look really sturdy and also not watersealed.

Additionally when looking at the switching current, make sure that it is a DC rating. AC current rating is usually higher, since it is easier to switch it off due to the zero passing.

Regards,

Tobias

[srikanth chilivery]

http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Kalyan Dash]

Can we use this kind of switches as master switch?