I would like to build the switching circuit in the diagram below. The circuit is used to run the 12V d.c. 10a pump (P). (I don’t need anything to the right of the pump)
The red and black leads from the pump are 1/4" spades. The while lead from the pump is 1/4" female spade.
I have the fuse and inline fuse holder. It has 1/4" spade leads as well (male and female).
In lieu of the battery, I would like to use a AC/DC wall plug transformer.
This will be mounted in a relatively unlighted area, having illuminated (rocker?) switches would be nice.
Can someone help me with a BOM for this project?
We can most likely provide a list of parts that you can choose from for each of the components, however the more information we can get the better we’ll be able to advise on the components. What dimensions are you working with for this project? Additionally, are you expecting to solder some components together on a board or will you need connectors for everything? Please advise.
Hi Klint –
Dimensions – I’m rather unlimited in space where the enclosure will be mounted. Something in the neighborhood of 4" by 6"? Could be larger/smaller as necessary.
My soldering skills are so-so but I can get it done if necessary. That said, connectors would be better.
I have some concerns regarding some parts of the diagram, as it looks like override switch is supposed to shunt the positive, however it seems to possibly put the pump and running light in parallel, which would indicate the pump is still running. Is the override switch supposed to be directional control?
As for the power supply, we do have some options that can output 120w, however it’s important to make sure we have both your regional power and plug type accurate. Are you going to be operating on a 90~240VAC and 60Hz system?
Regarding the override switch, the documentation says “The white wire can be connected to a running light to indicate when system is in use and/or as a manual override switch.”
fwiw, the IC Accessory (IC in this case is a marketing name for “Intelligent Control”) in the diagram is a water drain with an internal switch that is activated when water is detected in the drain. My understanding of the override switch: when both the isolator switch and the override switch are turned on, the pump will be activated and light turned on regardless of the state of the drain switch. Does this make sense?
re: power supply – this will be operating in the US – 90-240VAC/60Hz
Thank you for sharing that bit regarding the white wire; it would make sense that the pump would have essentially a “driver” to determine whether it should be one or off and so for another input to act as a manual override to force the operation falls in line with that logic.
Although there are some open case modules that could possibly work, I am assuming you want this with as many finished/full modules as possible. If that is the case, then 1866-3673-ND should work for the power supply.
Because your fuse holder has 1/4" spades on it, we’ll need a connector that will split out the positive and negative and allow you to put a quick connect on there. Part 2092-KPJX-CM-4S-ND is designed to mate with the connector on the power supply and its solder cups allow you to put the desired wire in. The key here, however, is that positive is on pins 1&2, and negative is on pins 3&4, but you’ll need them to converge as you only have 1 positive line going to your fuse (see the diagram below for reference). Additionally, you’ll want to make sure the wire can handle the 10 amps going through it without it overheating, so I recommend at least a 20awg wire to handle this.
If you want to continue with these power supplies and connectors, along with the fuse you already have, I’ll need to know what the size of the quick connect terminals (both male and female, although I assume they’re probably the same it’s best to “measure twice and cut once” as they say). Once provided, we can see if there is something in our catalog that fit the dimensions, and we will proceed from there.
Yes — let’s proceed as you’ve described.
All of the connectors on the pump are 1/4”. The black and red are male, the white is female. The connectors on the fuse are also 1/4” male on one end and female the other.
Also, sorry for not including the info about the white wire and drain switch earlier. No excuses for revealing system requirements slowly!
My apologies; you’d stated previously that they were 1/4" terminals on all of them and it just slipped my mind!
For soldering to the connector, I suggest some plain old 20 awg wire in both red and black (to denote the positive/negative relationship) which you can find HERE for red and HERE for black. I’ve included a few options for length. From here, they’ll need to be joined/split, and one of the easiest ways to do this will be utilizing a splice connector. There are a few options to choose from, which you can find HERE, however you will want to ensure that you have two (one for the positive terminal and another for the return).
If you prefer not to use the splice connector, you could crimp some quick connect terminals to the wires instead. Part 298-16682-ND should be crimped to the wires in which you will then use part WM13611-ND to join them to the fuse. Note that these will most likely be necessary on other parts of the circuit as well such as going to/from the switches.
Because you’re using a power supply that plugs into the wall, I am wondering if the “isolator switch” in the circuit is going to be necessary. Normally it’d be an absolute necessity in order to remove power from the circuit, however with your modification if you wished to perform any maintenance you could simply unplug the power supply from the wall. Doing this will allow us to use a single switch in the circuit instead of needing two separate switches.
If you do go in the direction of just a single switch, part 32-CRSL1A12V3M9-ND is illuminated and has markings to indicate it’s status, and it comes with the necessary quick connect terminals. I do have some concerns for going the illuminated route, however. My first concern is that you will need to make another split after the fuse so power can go both into the pole of the switch and the LED. This is going to be in addition to the necessary split after the switch so power can go to both the white and the red line. The more splitting that happens, the more potential resistance we add. This ties into my second concern, which is the maximum power provided from the power supply. It is intended to provide 12V and 10A, most of which will be consumed by the pump. The more components added to the circuit means more power draw, which in turn will either force the power supply to work beyond it’s intended parameters or it will leech the power from the pump depending on the circuitry in the power supply and pump. Some options without the illumination can be found HERE.
Considering the above regarding the power draw, did you still want to have a running light? If so, what sort of light were you thinking?
Let’s omit the isolator switch and running light. Override switch w/o illumination is good too.
Thank you for your patience on this one. With all of this together, the BOM should be as follows:
|DigiKey Part Number
|AC/DC Power Supply
The BOM is based off of the understanding that the circuit will be modified to work as below:
As a reminder for the DIN connector for soldering:
Good luck on your build, and if there is anything else please do not hesitate to ask!
Thanks Klint! This is great.
Any recommendations for a board/enclosure for mounting the receptacle and switch?
One other concern I would have is the actual characteristics of the pump current draw under load. Is that 10A spec an absolute max, or a nominal running spec?
It would not be uncommon for a pump to draw 5x or more the typical current during start-up. If your 10A rating is nominal rather than absolute max surge current, then you’ll almost certainly need a power supply rated much higher than 120W. You can help mitigate this to a degree by using more output capacitance to provide a short-term surge current source, but I would still recommend more power.
Thanks David. Here are the specs on the pump
OK. The “soft start/ soft stop” portion is more reassuring that you won’t have as big a surge as is sometimes the case. I believe the typical automotive fuse is fast acting, which indirectly implies a lower steady-state current for your pump.
With this info, it would seem that a 120W supply might be sufficient. However, I would still lean toward a bit higher power rating, as it would be less likely to run into over-current shutdown/hiccup behavior, and it would likely last longer by running further below its upper limit ratings.