KJD 17 wiring to 230vac single cap motor question.

[boyd]

I have started a new thread because this has me stumped and the outcome will be good advice for all.

I have wired two, 2.2kw 230vac dust extraction motors to a box containing several SSRs being 24-380VAC 80A with 3-32vdc trigger.

The dust extractors came from the same factory.

One extractor has just two wires coming out of the motor and is a double capacitor motor. All the internals allowed me to just put a SSR in series with the phase which works great. I did need to up the rating of the SSRs to 80A as the 40A ones were too small for the initial rush of current and/or were rated incorrectly.

The second dust extractor has two wires coming out of the motor and two wires coming from a single start capacitor. This one was controlled by a KJD17 switch. I wired it with the start capacitor in parallel with the 230vac input thinking that was correct as per my picture. But no. Boom. I blow my workshop fuse. After looking at the switch, I think I need to wire the start capacitor in line with the phase to bump the input to get it spinning. Not sure. Am about to try???

I would really like to hear from someone who has worked with one of these before. There is no centrifugal switch in the motor. Just two red wires coming out and two white that go straight to the cap.

This system is huge. I have completed everything and am about to commission it. I have fully automated my workshop. Now when I switch on any machine (one out of eight):

1. The machine starts.
2. The extractor starts.
3. The corresponding pneumatic controlled 100mm pipe gate opens allowing dust to enter the extractor.

When I turn off the machine:

1. The machine stops immediately.
2. The extractor continues to run for 30 seconds then stops. I have built a simple delay switch with a cap, two diodes, a resistor, npn transistor and small relay. The capacitor determines the length of delay along with the resistor. I can post this circuit if anyone wants to see.
3. The pneumatic 100mm gate from the machine shuts.

I am very proud of this massive project and plan to show it off in a post with pictures. I have worked out I will save at least 40 hours a year. At least!

But keen to hear about this single phase motor issue I am having?

 

[Bluejets]

All of your wiring is incorrect.
Can you supply a factory drawing of the motors and their connections.?

 

[boyd]

Hi Bluejets. Darn. No. Unfortunately its a chinese machine. No data plate except for ratings. No access to manufacturer.

It was connected to a KJD17 switch which I am about to dismantle to see how it works. Pic attached.

I don't know what U< is but I thought it was an under-voltage protection although it goes to the start cap.

Without the cap connected it sometimes will run but sometimes not - obviously a start cap. But no centrifugal switch that's for sure.

I might be prematurely posting here and just need to take a proper look at this setup. Basically the machine came with a three pin single phase plug.

I believe the motor and the KJD-17 switch are a matched item. For my purposes I need to replicate that somehow so I can control it with a SSR.

Please standby I will get more information. Pain really. The other extractor works fine and everything else in the circuit does as well.

Oh. BTW. Everything is safe and well earthed inside enclosures.

 

[Minder]

You should have two winding's on the motor start and run, usually the common point is internally connected if only one rotation dir need. Making 3 leads, 2 for AC in and the other for seiries'ing the cap with the live.
The capacitor should be in series with the higher resistance winding.
M.

 

[boyd]

Hi. Thanks Minder. I actually commissioned my whole system last night with a successful outcome! Massive project and full success. Oh. Hang on. Two minor issues, one being the 10A breaker tripped with the simultaneous switching on of two machines. Second issue was the power line managed to induce an interference signal into my control line making my low voltage relay bank flicker.

Back to the motor. It has four wires. Two white. Two red.The two white wires go straight through the body to the cap with zero resistance.

I have attached a picture. I am stumped to be honest and if I cant sort will have to pull the motor apart to see what goes where which is silly considering it went well with the KJD17. If I put power on the configuration it is in now with the cap in parallel it blows my breaker. Disconnect the cap and it hums or starts very slowly.

I have removed and checked the cap which tests out fine.

I feel like an amateur here. Built this amazing system and I cant work out how to wire in a darn single phase motor!

It says its a 2 pole 2.2kw single phase motor. Gee. The exact same machine next to it just wired up perfectly although its a double cap motor.

I am going to have to pull it apart huh? Oh and I have attached a pic of my SSR box. Sorry its messy but I need to get it all working before I can tidy up the wires proper. Like I say. The other machine runs fine with this SSR system.

 

[Minder]

I can see why it blew the breaker with the cap across the supply as well as not getting it rotating.
If you were to spin the shaft it most likely would run without the cap , either direction.
The motor is most certainly going to have two winding's, start and run, the cap has to be in series with the start winding.
The motor is probably going to be a PSC (permanent start cap) motor.
M.

 

[Bluejets]

The motor is most certainly going to have two winding's, start and run, the cap has to be in series with the start winding.
The motor is probably going to be a PSC (permanent start cap) motor.
M.

M x 2 ..............such as this.......

 

[boyd]

Thanks. You have I believe cracked my problem. One white wire goes to phase. The other white wire is just a signal to the KJD17 under voltage protection. So I just need to measure it out to get the wires correct with one white cut and blanked.

Yes correct in previous history without the start cap I have found a motor will spin if you hit the shaft.

Standby I will try.

 

[boyd]

Done. I cut one of the white wires going into the motor. The other white wire I soldered into the phase.

It runs. Slow to start but runs. I think it appears slow to start as the machine next to it is a double cap motor and is almost instant to be at speed.

In fact, yesterday I ran both extractors together without any issues! The system works. I will create a thread soon showing all the systems in place, how they work, and the simple timer circuit I built with a cap and npn transistor.

Many thanks for your help.

 

[Minder]

Unless highly loaded it should not really be slow to start, are you sure you have the correct winding in series with the cap, as each winding is different.
M.

 

[boyd]

Hmmm. Gee to be honest I dont know without taking the motor apart. The resistance of the windings are so low there is no way I can identify which is which.

What I will do though is put the cap onto the other input to the motor. Although I do remember when I got the machine it was a slow starter. There is not much physical resistance as it is just a big fan really. I will investigate further.

 

[Bluejets]

Along with getting a reading and work out which is which, really need to wack a tong meter on it and see what it is doing before you cook it.

 

[Minder]

Many PSC motors have identical start/run winding's, making it easy to reverse, yours could be one of these.
It is usually easy to detect the difference on the type with unique run/start winding's.
M.

 

[boyd]

By wacking a tong on it you mean check the current draw? There is a KJD12 in line to the extractor which checks for undervoltage.

I have used the machine now for 2 days and all has been great. Just a slow starter. The two extractors are controlled by SSRs and are currently being fed 230vac simultaneously. One starts immediately and the other winds up slower. Same machine different motors.

I will say though, some of my other machines take a wee while to start too so I am not too concerned. Plus if there is a voltage drop the KJD12 will drop out.

I do have to admit I am very proud of my system. Just a couple of minor issues to iron out and I have a workshop which will save me almost 80 hours a year, possibly more as I dig further into automation.

Pneumatics alongside basic electronics and electrtical systyems are definitely the way to go. Simple to control and robust. And safe as all the high voltage is well hidden. Although I consider 4kv high which is what our ROV runs on ha ha. I love it. Anyway, not sure anyone in NZ has a home DIY workshop like mine ha

 

[Bluejets]

By wacking a tong on it you mean check the current draw? There is a KJD12 in line to the extractor which checks for undervoltage.

Yes, current draw....... not to be confused with voltage as you seem to be.