Need Advice On The Best Type of Switch For This Application...

[Reloadron]

Place the fuse in series with the high side of the load.

You can likely use an automotive fuse rated for 32 VDC. I believe this began with a 36 VDC application and I don't believe the additional few volts will matter. Auto supply store should have what you need. That or take a look at McMaster Carr Supply if you have one locally.

Ron

 

[rs14smith]

Place the fuse in series with the high side of the load.

Ron

Just confirm this for me: an easy way I can tell which side of the motor is the high side is by hooking up a multimeter in the circuit while the motor is running, and if that multimeter is showing a "positive" value, I should place the fuse in series in that direction...

Ehhh it'll probably be easier to just draw it out as I confused myself writing that out above lol, so I provided a schematic below:

 

[rs14smith]

After reading this, https://au.answers.yahoo.com/question/index?qid=20070818225445AA7zFfx, it appears it needs to be on the positive side or in other words, as closest to the power supply as possible. Some even suggest placing it on both the negative and positive side. So it seems from the circuit I just posted, the fuse is only on the negative side which is incorrect? So I should have that blue box on the positive side...and if the fuse is cheap, I'll just have another one where the blue box is currently placed?

I think I'm getting it now...

 

[KMoffett]

No need or advantage of having two fuses. Convention is the fuse goes in the positive side between the battery and load, with negative being common or ground. In your circuit it can be anywhere in the series circuit.

Ken

 

[rs14smith]

Alright, so the last thing I need to confirm is if I'm picking the right fuse for the type of fuse holder I'm trying to buy off Amazon:

Fuse Holder: https://www.amazon.com/gp/product/B0002KR88A/ref=ox_sc_act_title_2?ie=UTF8&m=A1IBW2HULNJLEY

25A Fuse: **broken link removed**

The fuse holder said it fits ATC fuses so I assume the fuses off eBay should work fine? I do not know a lot about fuses as far as if one type is better than the other, but I do like that this fuse will shine an LED if it is blown.

 

[KMoffett]

Not knowing the physical construction of your circuit layout...I'll say yes the holder and fuses will work. Note that the LED will only light after the fuse blows if there is still a current path through the circuit that caused the fuse to blow.

Ken

 

[audioguru]

An SSR burns out immediately if it is overloaded.
A fuse burns out in a lot more time so kiss your SSR Goodbye.

You need a current-limiting circuit to protect the SSR while the fuse is warming up.

 

[rs14smith]

I think audioguru is right as my SSR appears to be nonfunctional now. Here is what happened:

-I supplied 12v to the motor with the SSR/fuse/diode etc. in the circuit: circuit worked fine
-I supplied 24v to the motor with the SSR/fuse/diode etc. in the circuit: circuit worked fine
-I supplied 36v to the motor with the SSR/fuse/diode etc. in the circuit: I kissed my SSR goodbye. (SSR no longer working correctly)

Basically, the SSR's output stays closed allowing the current to flow, and never opens back up no matter what I'm supplying to the input of the SSR...so it's useless (or trash) now.

So then, I hooked up a multimeter in the circuit to measure the no load current, and found the following:
-With 12v getting around: 2A
-With 24v getting around: 3 or 4A
-With 36v getting around: did not fully check since the motor is loud and didn't want to disturb mother

But I think it's safe to say that the current with "no load" will not go over 10A, so since my SSR can handle 40A, I don't think it was a current issue, nor a voltage issue...so I'm completely lost here. I hope someone can help

I did order an extra SSR, so I am prepared to give it another shot once I figure out this mystery.

 

[Reloadron]

What exactly are you using for your DC source and what exactly is this DC motor you have been experimenting with? I figure this all connects to your current measuring thread. I am just real curious as to your DC supply.

Ron

 

[rs14smith]

What exactly are you using for your DC source and what exactly is this DC motor you have been experimenting with? I figure this all connects to your current measuring thread. I am just real curious as to your DC supply.
Ron

The DC source are regular 12v deep cycle batteries. The DC motor is a motor in an electric motor, which is just a basic induction motor that has a the lawn mowers blade attached to it.

 

[Reloadron]

Batteries, OK. I don't see any reason off the top for the SSR to have failed. Possibly a defective unit.

Ron

 

[rs14smith]

Batteries, OK. I don't see any reason off the top for the SSR to have failed. Possibly a defective unit.

Ron

One thing that I did notice was that when I hooked up the wire to the 36v setup, there was a huge spark which I think had something to do with it...not sure what you call it, but the startup current which is 2x or 3x the regular no load current.

All I know is, the connection spark became bigger and bigger when I added one more battery in series.
12v: really small size spark
24v: medium size spark
36v: large spark - burnt the wire/battery terminal connector a little and scared me some - I think I'll be wearing some safety glasses next time lol

Like I said, I know the more power you have, the larger that spark is going to be, but I'm thinking with the 36v setup, the SSR couldn't handle the amount of "startup current (i know this isn't the right term)" that was deliver...as I don't see where else anything could go wrong since the system worked for 12v and 24v.

 

[rs14smith]

Ron, my circuit has changed somewhat since my original post here so I'm wondering if I should just start a new thread as some may read the first post and respond to that when the requirements have changed now, however, it's still somewhat apart of the same system?

 

[Reloadron]

I actually agree that you may want to start a new thread. Just make sure you explain everything in great detail. Personally, sometimes I believe a thread drifts so much off target (with changes) that it becomes benificial to just start a new thread on the new subject.

Ron