[Regnar]

So Im starting to plan out my Controller box and I was thinking could I use a phone jack and make my own wires (shielded of course) to hook up my motors and limit switches. Maybe even a Lan Jack because its alittle beefier. I seen the trailer wire hookups but wasnt to impressed with the ones at walmart and for the price I might as well order cannon plugs. What is your guys take on the phone jack hookup?

[NC Cams]

Great connectors for phone lines - may not work well at all for motors, too much current.

Seriously, any connector has a rated current and voltage. From a number of tests we conducted when we we're HEAVY into electric R/C car racing, for low current appllications, almost any connector will suffice.

However, when you start to pull decent current (say more than an amp or so) or you have a connector that will encounter NUMEROUS make/break insertions, connector integrity starts to become a CRITICAL factor.

Basically, you can (and some people will) kluge up ANYTHING to make it work. However, if you want something to NOT have problems and NOT have durability issues, spring for the best connectors that you can hardly afford. If you want fool proof connectors, use the die cast MIL Spec pieces.

When these are used, the machine simply runs and goofy a$$ connector issues are GONE for good. Pricey? Yes. Lacking the dollars for these? Consider the used of WeatherPak connectors made by Packard Electric/Delco.

These automotive grade connectors come in various size and current ratings that do a good job of making and maintaining vibration and environmentally resistant electrical connections in extreme operating environments. THe environment of an underhood application is EASILY more severe than many/most CNC applications.

PS: don't buy the pigtails and then start splicing. Buy the proper wire and the proper terminals and crimping tool and do the job right, from terminal to terminal. By doing so, you will NOT become disappointed.

As far as shielded connectors go, the MIL spec stuff is still the way to go as this system maintails R/F shielding to/through the connector which the WeatherPak stuff doesn't.

[Al_The_Man]

So Im starting to plan out my Controller box and I was thinking could I use a phone jack and make my own wires (shielded of course) to hook up my motors and limit switches.

Which end are you thinking of using connectors? For limit switches it is usual to hard wire them each end, you could go into the enclosure with strain reliefs at the entry point.
Connectors are nice, but it often pays to keep them to a minimum if possible, they are often the cause of intermittents and ingress of oil, coolant etc depending on the machine.
The only real advantage I have found is on multi-connector servo's with encoders etc, where if you need to change one out it is very easy to do if connectors are fitted.
Otherwise I tend to hard wire where possible.
Al.

[Regnar]

Al I was trying to make the controller have its own enviroment, one in which I could control from dust and tempature. My ideal is to make a firewall and have the wires pass threw but have a connection point. I have seen people use 9 pin buses, microphone connectors, and military cannon plugs. Just trying to see if this was could be an alternative (trip to Home Depot)

[Al_The_Man]

That is one reason I mentioned cable strain reliefs. If by connection point in the enclosure, Terminal strips are one of the best, It depends on what configuration you are trying to wire, and where you intend using these connectors?
If you want connectors similar to MS style, Cannon etc, the next best and cheaper is the CPC style from AMP.
Al.

[veeguy]

I firmly believe the best connector is *no* connectors. I'm an industrial electronics tech, and 9 times out of 10 a poor connection can be traced to a connector.

If you don't anticipate needing to break the connection often, make the connections solid. If your motors have pigtails, extend them by soldering wires onto the existing wires. To protect and insulate the splice use a piece of shrink tubing about 3X the wire diameter. Instead of heating the tubing to shrink it, use a squirt of hot melt glue into one end of the tubing. The hot melt glue will encapsulate the splice, and shring he tubing at the same time, making a waterproof connection. I have used this trick often to splice submerged instrumentation cables at our wastewater treatment plant. Some of them have been in use for several years this way.

As to the question about using modular connectors, don't. A modular connector only supports a few milliamps as it is a data connector, not a power connector. As a cheap connector, Molex connectors are hard to beat. If you only need 4 wires for a bipolar motor, floppy drive molex connectors are very cheap, and will carry 20 (or more) amps at 24 volts. Thats just short of 500 watts.

If you wan shielded cables (not necessary in my opinion) just use shielded cable and ground the shield on one end (either end will do) The short length of wire inside the molex won't affect anything.

veeguy

[RCjunkie]

Try this place
http://www.mpja.com/
i get a lot of power supplys for a CNC foam cutter

[Regnar]

This is an example of what I was going for.

[Al_The_Man]

'D' type connectors maybe fine for encoders etc, their limit on wire size is around max. 20~24g.
Check out the CPC AMP connectors as per my previous link, they are sturdier and carry more current, they have bulkhead mount as well as inline. You could always use them just for the motors if necessary.
Al.

[spindlenut]

DON'T use phone plugs. What's to lock them? They're made for easy disconnection, precisely what you don't want on an industrial machine. They could probably loosen and come apart just from machining vibration. And, if you pay attention to the construction, the connections are inline, meaning one will touch before another during insertion/extraction. Great way to short out something if that happens under power. They're made for two or three signals, when plenty of CNC circuit cables need way more than that. No advantage, but plenty of disadvantages. Save the phone plug for your stereo.

Mil-spec circular metal (commonly called Cannon, even though Cannon hasn't made them for a long time) are best, IMO. If they're beyond your budget, check a military surplus store. I've run across them before (used), for cheap.

Molex-type (or maybe they're actually Molex) are even available in Radio Shack. These are rectangular white nylon, don't tend to come apart, (in fact, sometimes they're a real PITA to take apart) and can carry up to 12 circuits.

Al's idea is good about the CPC. They're cheap (the "P" means plastic), assemble EASY (push together, turn the collar about 1/4 to lock), have decent cable clamps. Probably available in a good industrial electronics store. Otherwise, try Allied (and other mail order places, too, I just prefer Allied).

[Regnar]

Al and everyone else thankyou for pointing me into the right direction. I am not fully up to speed with electricity just yet, so to me if the two wires touched I was good. I do like the CPC and will be going that route. I dont think I would have ever used phone jacks, well I was really thinking hard for the limit switches, but hey nothing lost, knowledge gained.

Now to search to figure out how to connect more fans say 5 or so. I have the xylotex power supply with his stepper board fan and motors. Could I just get more fans and run it off of the power supply? If I can do you run it in series or parrel?

And if this is just becoming a real pain in the a$$ to answer this idiots simple questions could you point me in the direction for the idiots guide on electricity.

[spindlenut]

>>>I have the xylotex power supply with his stepper board fan and motors.

Sorry, I'm not familiar with xylotex. What matters is what voltage the fans require, and are they AC or DC. Most cooling fans take little wattage (watts=volts * amps), so you have to know if the power supply has the extra wattage capacity to support the fans. The fans should have the wattage rating marked on them. Add the wattage of all the fans you plan to install. If they are 115volt AC fans, then you could probably find a spot to tap power from easily. A power supply might require a harness with a particular plug to get the power from it. Of course, you can probably tell that because you have it there to look at.

Fans are usually rated in CFM (cubic feet per minute) in air that they move. More air from more RPM or higher pitched blades generally means more wattage required. Select accordingly.

[NC Cams]

Re:molex (computer connectors) connectors: We originally used them on our R/C car battery connections. Result: after a couple of insertions/removals, they would NOT reliably maintain continuity - under vibration, they'd go momentary and the car would go nuts or dead.

After losing some races due to connector issues, we then did extensive resistance/conductivity testing under constant current loading of 5, 10 and 20-25 amps. The molex (white connector, ala HDD power supply) had some of the highest resistance/voltage drop of any connectors we tested. In a word, they sucked for use in high current density applications.

We then went on a search and looked into a number of small size, high current densigy connectors. The results were interesting.

The common molex connectors were the worst. Hard wire plus solder was absolutely, undoubtedly the best. We found an unusual double wipe "blade" type connector from a Ford that fit a rear window defroster harness to be the next best thing to a hard wired and soldered connector.

Trouble was that they were hard to come by, didn't have universal plastic holders so we had to craft up shrink wrap insulation to make them plug and play.

I repeat, the BEST industrial connectors are the MIL spec, gold plated variants. You can obtain them in high current large pin versions and multi pin, signal current level variants. Considering the fact that Fanuc, Bridgeport and the military use them on mission critical devices, the fact that they work can't be denied.

Price (new) of the MIL Spec stuff can be an issue - check out surplus houses for deals, they can be salvaged with some small work. They are NOT cheap new. This is why I mentioned the use of WeatherPak's.

The WeatherPak's are used in automotive underhood applications. They use them in high vibration and critical computer sensor feedback situations. They WILL withstand multiple insertions and removals without losing conduction integrity. They are affordable and far superiour to Molex IMO.

After having first hand tested various connectors under current draws as high as 20 amps CONTINUOUS, I can say that the order of preference due to performance would be hard wire and solder, then MIL Spec, then the wierd Ford terminal, then WeatherPak.

The Molex "computer power connectors" would not even being worthy of consideration from my experience.

You are more than welcome to ignore the above bench dested/evaluated recommendations and use whatever connector suits your agenda and/or budget. The afore mentioned recommendations provide affordable variants for just about any budget.

PS: leave the molex stuff for the computer components. They are NOT robust enough for CNC use.

[veeguy]

Funny, I've been using them with no problem on my lathe steppers for over 2 years. They work fine. They are tin plated. When you put them together, the tin to tin makes a great connection. I do not go pulling them apart every few days like an RC battery gets used, maybe thats the difference between your and my experiences?


I use silicon paste to insulate the connectors inside, then wrap them with silicone splicing tape.

veeguy (master Electronics Technician / learning machinist)

[NC Cams]

Veguy: the silicon paste is saving you grief and heartache.

Tin plated connectors will readily tarnish/ozidize, especially in a shop that has lots of solvents and chemicals in the atmosphere. IT is not uncommon for us to have to reseat and/or clean the pins of tin plated IC's and connectors in our older equipment.

Want trouble free connectors? Use gold plated ones. They will NOT oxidixe and the premium is quite small.

Whether it be molex or the phone connectors, they work well in the intended environment. They are NOT necessarily designed or intended for high/higher current applications. All I can say is that our testing conclusively showed that there are better options if you're looking for bulletproof connectors that will/may pull high power in a less than benign environment.

[dvbrownell]

I would agree with those that have suggested the AMP CPC series of connectors. I have used them for the last 15 years for most of my projects and instalations that require that type of connector. I use the crimp on contacts but if you want to save on the cost of the crimp tool the contacts are available in a solder cup or tab depending on the series of contact you are using. Ordering these connectors can be a little confusing because all the parts are ordered separately and there are often a number of different options for each part and you can order a recepticle and plug with the same number of contacts that will not mate. For this application I would use the series two connector in the sealed version, reverse sex and the contact that has the thickest gold plating available if you plan to mate and unmate the connectors often. The standard sex version is backwards in my opinion as it uses pins in the recepticle and socket contacts in the plug. I have yet to have a issue with these connectors that couldn't be attributed to some form of human error and we're talking about literally thousands of connectors and tens of thousands of contacts.