i want to control 6 1HP 3 phase motors. switching them on manually everytime is becoming a pain. is it possible to have one Arduino control 6 3 phase motors? i have attached a pic of my current setup. motor starters connected to single phase preventers with time delay for load distribution(each starts 10 seconds after another). will i need to take these off and go for 3 phase relays? they are very expensive!! i have seen some home automation projects mention use of single phase relays for starting motors. will it work if i connect one line of 220v to single phase relay and expect phase preventer to do its job when i cut off the line using Arduino?
If you leave the single phase preventers in the circuit, I'm sure they could be adapted. At the end of the day the start button is a momentary contact switch (normally open). whereas the stop button is a normally closed momentary break switch.
All you need to do is put a relay driven switch in parallel with the start button and another in Series with the Stop button.
With a 2 relay board setup within each preventer housing, you could then interface these to the arduino fairly easily. (6 output wires total).
You could then have them triggered on a timed basis using a single button, or even unattended based on time of day (that's probably a bit dodgy. I suspect those motors are driving some serious equipment)
The nice thing about this setup is that the preventer circuits would still function independently.
KenF:
All you need to do is put a relay driven switch in parallel with the start button and another in Series with the Stop button.With a 2 relay board setup within each preventer housing, you could then interface these to the arduino fairly easily. (6 output wires total).
thank you for the suggestion. i am not sure i got it all right. were you suggesting i wire the relays to start and stop of motor starter? that makes a lot of sense and simplifies my problem greatly!! i'm confused with the 6 output wires you mentioned. i will have two relays driven by 2 output pins, so will six motors will need 12 output pins from arduino? can i drive both relays with same output pin of arduion? thanks again
edit: btw they drive motors with paddles that flap water around to increase dissolved oxygen 
nomad1901:
thank you for the suggestion. i am not sure i got it all right. were you suggesting i wire the relays to start and stop of motor starter? that makes a lot of sense and simplifies my problem greatly!!
Kind of. The single phase starters you have. you can use a relay that effectively shorts out the start button when active.
The stop button is a bit more of a problem. This will be normally closed. So to have your arduino able to ALSO stop the motors, you'd want to put a normally closed switch in series with this. (this could involve some slightly more butchery than the start button) This new normally closed switch will be part of a second relay. I'll see if I can draw a diagram.
nomad1901:
i'm confused with the 6 output wires you mentioned. i will have two relays driven by 2 output pins, so will six motors will need 12 output pins from arduino?
I'm not surprised you're confused. You distinctly said 6 motors, but I was thinking 3 motors. So yes 12 inputs.
nomad1901:
can i drive both relays with same output pin of arduiono thanks again
Not really.
The stop switch wants to be normally closed, only opening to stop the motors.
The start switch wants to be normally open, only closing to start the motors.
BTW Any arduino from the UNO upwards can cope with 12 outputs easily. (even some of the tiny ones can)
aaahhh ;D ... got it now.. thanks a ton!! will implement for a single motor first and see. cheers!!
Judging by the photo and use of green active conductors on the door wiring,yellow on the starters,no earth on the door,no protection around main isolator, lack of protection on outgoing cabling and worse yet, no apparent earthing running with outgoing,not to mention lack of knowledge or qualification, I'd have to say a potential for a rather disasterous ending is ahead.
bluejets:
Judging by the photo and use of green active conductors on the door wiring,yellow on the starters,no earth on the door,no protection around main isolator, lack of protection on outgoing cabling and worse yet, no apparent earthing running with outgoing,not to mention lack of knowledge or qualification, I'd have to say a potential for a rather disasterous ending is ahead.
I don't know where in the world this is located and even if I did I wouldn't know the relevant codes they follow. In some countries this would look like a thoroughly professional installation 
bluejets:
Judging by the photo and use of green active conductors on the door wiring,yellow on the starters,no earth on the door,no protection around main isolator, lack of protection on outgoing cabling and worse yet, no apparent earthing running with outgoing,not to mention lack of knowledge or qualification, I'd have to say a potential for a rather disasterous ending is ahead.
What he said, X10.
KenF:
...At the end of the day the start button is a momentary contact switch (normally open). whereas the stop button is a normally closed momentary break switch.
That is a rather large assumption. I'd be more inclined or believe they are in fact manual motor starters. So, this a question for the OP: Have you opened the motor starter boxes? What do you find inside? Do the push buttons are wires coming out them or are they mechanically linked to a three phase switch? You better look before you leap. And don't forget your parachute in the form of an electrician that knows how to keep you from killing yourself...
looking at the photo. the large boxes appear to be manual motor starters.
the device in front might be a switch, or might be a circuit breaker.
the PX-101 is a single phase preventer.
although there has been a lot of care taken, great box, spaced well, etc. that part that scares me most is that plastic wire on the metal edge where the wires exit the enclosure. take some of the insulation from the stripped wires and make a guard. also, the open hole allows critters to enter.
at this point there does not appear to be any magnetic motor starters. ergo, no immediate way to connect these to an arduino.
can you open an enclosure and take a photo of the insides ?
also, a close up of the breaker and one of the single phase preventer.
with the water in the background, I would assume pumps. makes sense with the power. 1hp is not very large.
the motor starters would ( I hope) have overload heaters.
alas, if they are manual, then the choices are not great.
buy new magnetic motor starters. expensive.
buy new variable speed drives, probably less expensive than the magnetic starters
buy new soft start motor starters, oddly , more expnesive than VSDs these days.
buy 3phase SSRs. oddly, these might cost more than a VSD.
buy a definate purpose contactor, rated for twice the motor.
the definate purpose contactors would be placed after before the existing starters. the contactors would be able to be powered with lower voltage, a single signal from an SSR or relay. it is hard or impossible to get a DPC in 5 volts and the power needed as that would be risky for use with an arduino.
best thing is to lay our the schematic, post photos of the components and hopefully to data sheets.
one option that is not particularly good is to make a rocker button pusher with stepper motors. a threaded rod, springs to push the buttons and mount them to the starters. then save for magnetic starters and when they start to fail, swap them out and connect.
a note here is that most of the starters I use are line voltage, many are available in 120v coils here in the States. I buy the most common I can find so that parts are easy to get.
the last time I tried to get a 12VDC coil, it was 2 weeks. that meant to me, 2 weeks down time if it ever fails. I went with the 277v coil and a simple relay. both were cheaper than one odd voltage coil and both were in stock.
If that motor starter is a D.O.L. type, you should be able to mimic the pushbuttons with a simple pair of relays.
if the START closes a cirucit, and the aux contact hold that closed, you need a pulse to start the motor, then a second action to stop the motor. two relays, both close on start. one provides power to the start coil. the second would open the power to the start coil.
2 pins of output from an Arduino, but you could easliy use a shift register to multiply the output pins to the relays.
still like to see the data sheet on the starter.
bluejets:
Judging by the photo and use of green active conductors on the door wiring,yellow on the starters,no earth on the door,no protection around main isolator, lack of protection on outgoing cabling and worse yet, no apparent earthing running with outgoing,not to mention lack of knowledge or qualification, I'd have to say a potential for a rather disasterous ending is ahead.
never too late to learn right? the green wire on the door i believe is protective ground. we follow red yellow blue for our line. thats the color code our supply company uses and we adapt it. i hear you on outgoing earthing and protection around main isolater. we are working on improving our housings but all that is money we dont have right now. thanks for the concern i will try and be extra careful trying this out. we have about 500 of these and we blow a couple every month can afford one more. let me know if you have any advice for me
KenF:
I don't know where in the world this is located and even if I did I wouldn't know the relevant codes they follow. In some countries this would look like a thoroughly professional installation
third world and yes, this was done by a professional. the box was also fabricated to his requirement.
avr_fred:
That is a rather large assumption. I'd be more inclined or believe they are in fact manual motor starters. So, this a question for the OP: Have you opened the motor starter boxes? What do you find inside? Do the push buttons are wires coming out them or are they mechanically linked to a three phase switch? You better look before you leap. And don't forget your parachute in the form of an electrician that knows how to keep you from killing yourself...
these are DOL starters from L&T with NO start and NC stop, KenF suggestion made a lot of sense to me, im still waiting on the relay i ordered to try it out. electrician is responsible for the wiring you criticized, let me know if you can suggest any improvements to it.
dave-in-nj:
best thing is to lay our the schematic, post photos of the components and hopefully to data sheets.
i will post pictures as soon as possible. the starter is a DOL starter from L&T. and yes the motors have overload protection. i want to rule out all options before i invest in a 3 phase SSR. thank you for your inputs
dave-in-nj:
one option that is not particularly good is to make a rocker button pusher with stepper motors. a threaded rod, springs to push the buttons and mount them to the starters. then save for magnetic starters and when they start to fail, swap them out and connect.
this is as good as anything else for me right now! thank you! the industrial solution costs a bomb! if i can 3d print a housing that can keep the stepper motor in place im golden!! will try this as last measure.
dave-in-nj:
If that motor starter is a D.O.L. type, you should be able to mimic the pushbuttons with a simple pair of relays.still like to see the data sheet on the starter.
yes, these are DOL motors from L&T. their website does not have a data sheet or wiring diagram. i will take pictures as soon as i can post them here
Hi, the boxes will be simple DOL starters, KenF suggestion is probably the best, cost and implementation wise.
Now what is a "single phase preventer"
Is that a "3 phase monitor relay ", that is its output will not let the motor start if all 3 phase are not present?
Tom.............................
Pity we cannot read what is printed on the boxes.
nomad1901:
bluejets:
Judging by the photo and use of green active conductors on the door wiring,yellow on the starters,no earth on the door,no protection around main isolator, lack of protection on outgoing cabling and worse yet, no apparent earthing running with outgoing,not to mention lack of knowledge or qualification, I'd have to say a potential for a rather disasterous ending is ahead.never too late to learn right? the green wire on the door i believe is protective ground. we follow red yellow blue for our line. thats the color code our supply company uses and we adapt it. i hear you on outgoing earthing and protection around main isolater. we are working on improving our housings but all that is money we dont have right now. thanks for the concern i will try and be extra careful trying this out. we have about 500 of these and we blow a couple every month can afford one more. let me know if you have any advice for me
KenF:
I don't know where in the world this is located and even if I did I wouldn't know the relevant codes they follow. In some countries this would look like a thoroughly professional installationthird world and yes, this was done by a professional. the box was also fabricated to his requirement.
avr_fred:
That is a rather large assumption. I'd be more inclined or believe they are in fact manual motor starters. So, this a question for the OP: Have you opened the motor starter boxes? What do you find inside? Do the push buttons are wires coming out them or are they mechanically linked to a three phase switch? You better look before you leap. And don't forget your parachute in the form of an electrician that knows how to keep you from killing yourself...these are DOL starters from L&T with NO start and NC stop, KenF suggestion made a lot of sense to me, im still waiting on the relay i ordered to try it out. electrician is responsible for the wiring you criticized, let me know if you can suggest any improvements to it.
Green wiring on the door is going to some type of switch, not an earth for the door.
International color codes have done away with yellow active conductors 20 odd years ago, mainly because yellow/geen is the accepted code for earthing.
As for a professional who built the board, ...nope.
Advice, get a decent electrician.
If the starters have a magnetic coil then the Start would close a circuit and that would allow the coil to pull in. the coil would also be fed from a Normally Open contact (auxiliary contacts) inside the starter housing. this would allow the coil to take a pulse input, close the mains coil, then feed the power through the aux coil to the starter coil. this would keep the contact closed as long as the mains power was on.
the stop would interrupt that power and remove power from the main coil.
simple enough.
in order to automate these motor starters, you would add a twin relay. one of the two relays would be to send power to the START circuit. once that has been sent, the relay is then turned off and the unit would run.
to turn off, you would then energize the second relay, wired Normally Closed, and this would open the circuit to the coil and the unit would turn off.
That would mean that for each starter, you would need one twin relay. easy enough to add.
the photo shows 6 starters. I do not know the tolerances, but it might be possible to add this to the door, or side wall, or maybe between the existing starters.
if you check the data sheets for the model of the starters, I would hope this is the case.
programming.
taking a wild guess, this panel serves submersible pumps. therefore water flow is the actual process.
if these pumps are started manually, then you are the PID controller. you are the sensor and the logic program and the controller.
if it is for water level, then you need to add level sensors. These can be simple switches to start. if this is for irrigation and you are activating when dry, a different sensor would be needed.
I would highly recommend that once you have verified the equipment being used and that it can be controlled, that you start a separate thread for programming.
the existing panel appears that starter #1 does not have a single phase protector circuit. not sure why or why not.
but you could have the pumps come on in a sequence that would have them operate for so many hours per pump so that they all have about the same number of hours. for a little more, you could add a real time clock and a SD card and collect the data on when the pumps turn on and either calculate hours in the program or when you evaluate the data.
found a horrible sketch of a starter. as I suspected, the START is NO and closes a circuit. and the STOP is NC and opens a circuit.
the START is fed from one of the mains and the STOP is powered after the starter is closed, but on the SAME LINE. if if you are using L3 for the mains, then T3 for the stop.
if you add a new pair of relays and connect then to the switches, you can automate those relays very easily.
this is the easiest way to do this project.
CAUTION :
the wires will be at mains voltage levels. 230 volts or so. the relay will isolate them from the Arduino control, but they really should be inside of an enclosure.
a note about wiring. as noted, the wires leaving the panel are rubbing on the edge of the hole. any vibration, even going from hot to cold each night, will cause wear over time. these must be protected. you have many choices, but a simple wire clamp will be all that is needed.
for this new work, I would offer that every wire also needs to be protected from wearing on the hole it passes through.
TomGeorge:
Now what is a "single phase preventer"
Is that a "3 phase monitor relay ", that is its output will not let the motor start if all 3 phase are not
Yes, it does exactly that, we get 3 phase normally, supply company gives only single phase sometimes when demand is high to reduce industrial consumption( our computers will still run but heavy machinery can't ).
This one is single phase preventer from l&t. With circuit diagram.
Hi, so it helps you guard against having only a singe phase in your supply, what if one phase drops out and leaves you with two, now that's not single phase and it can do just as much damage. (Sorry had to sarcastically extend the meaning.lol)
The company that makes it sounds non-engish speaking, so "single phase preventer" could be a literal translation of 3phase monitor relay.
I would have thought you only need one of them as you have one 3phase supply.
I can see the importance of it here with so much relying on the 3phase and being unattended most of the time.
Tom.......