180 HP, 3 Phase Water Pump (Information Needed).

[Sajjadkhan]

high guys Its been a situation for me and i need your help to drive 3 Phase,180 HP, Delta connection water pump.

Specs:

Voltage : 380
connection : Delta
Amps: 252.8
P.F : 0.85
HP : 180

Some questions about it:

1. I want to operate it via controller after sensing water level. I am dealing with this much of current my first time.What is best to operate it: high current relay or Solenoid switch?

2. Amps = 252 approx. Does this mean that 252 Amps is flowing through every phase? As it is 3 Phase, do i need relays/solenoid switch with 252 or above rating per phase or 252/3 Amps or above rating per phase?

3. The wires in the connection box are of different colors representing different phases(i guess) so is it necessary to connect correct phase to correct motor terminal or should i connect randomly.

4. This one doesn't have a neutral right?

5. There are additional 2 wires connection in the box (Red Encircled) and i don't know what is it. i am thinking it as an RPM feedback, any thoughts?

I am attaching some pictures below, its a 80HP water pump but 180 pump is exactly like that. It was packed so i couldn't get the picture.

 

[YAS_HASHI]

Hi.

I can answer 1 to 3 questions. More details about the motor is needed to answer 4 and 5.

1. You should use magnetic contactor like this.
**broken link removed**

2. You need 252A switch each pahse.
380 x 252.8 x sqrt(3) x 0.85 = 141kW
180HP x 0.74 = 133kW

3. 3Phase motor must be connected to correct phase. Otherwise the motor may rotate opposite direction.

 

[chuckey]

The "other two wires", often these go to an embedded thermistor in the windings. They are normally 500 ohms which goes "high" if the windings over heat. Check them out with a meter. You can buy ready made overload units that take the 500 ohms and open the main contactor if it is exceeded. They also latch, else as the motor cools down the contactor would pull in again. . .
Frank

 

[Sajjadkhan]

Thanks for the replies guys.
1. Ok suppose if one of the switch didn't work (i.e. 2 phase are in contact and 1 not), what will be the consequences?
2. the wires are coming through a PVC pipe for protection and my luck... all are black. the damn electrician didn't care for the phase so i guess i need compare them with respect to neutral on the oscilloscope, right?
3. can u guys explain the colors of wires with respect to phase?

Thanks.

 

[chuckey]

1. the motor will take too much current and overheat and hopefully blow its thermal trip.
2 & 3 Just wire the motor up, let it run, it won't hurt it's self, if it does not pump, switch off and reverse the connections of any two wires.
Frank

 

[Sajjadkhan]

Thanks Guys.

 

[srizbf]

motors of these types make use of star-delta starter with set delay .
consider this when you design your control circuit.

 

[Sajjadkhan]

motors of these types make use of star-delta starter with set delay .
consider this when you design your control circuit.

1. I'll be obliged if you tell me the difference between magnetic contactor and starter.
2. What exactly do you mean by set delay. e.g. a some x sec delay or it starts the motor with a low rpm and then full speed? What will be the effect if there is no so called delay?

 

[chuckey]

A motor starter is a box that contains what is required to start THAT motor. A contactor is just a big relay optimised to switch AC voltages at a moderate to high power level (10W - 500KW ) .
For some applications , like running a conveyor belt the motor must be started at low power before its full voltage is put on it. Putting the windings in a star or Y configuration, puts 230V across each winding in the motor rather then 415 in delta configuration. It depends on the motor and its load.
Frank

 

[Sajjadkhan]

Well the motor will be used on Tubewell to pump water to tank 34 km far. There will be nine Tubewells and nine of these motors.

 

[mrarslanahmed]

The "other two wires", often these go to an embedded thermistor in the windings. They are normally 500 ohms which goes "high" if the windings over heat. Check them out with a meter. You can buy ready made overload units that take the 500 ohms and open the main contactor if it is exceeded. They also latch, else as the motor cools down the contactor would pull in again. . .
Frank

i haven't dealt with motor of such high rating. i have a question how many checks through embedded system are there for motors and are there separate wires coming form for each check?

And is there intermediate step between motor and embedded system?

 

[umery2k75]

@Sajjadkhan:

Well the motor will be used on Tubewell to pump water to tank 34 km far. There will be nine Tubewells and nine of these motors.

Well, I hope the motor and pump has been selected properly by keeping head and pressure in mind. I don't know if you have a static head pump or centrifugal pump and the types of outlet butterfly valves for operating the flow and other flow parameters. All these helps in deciding the type of electrical system you require.

1) Motor Protection Circuit Breaker with thermal overload is must, which takes the 3 phase incoming supply and outputs it to the main 3 pole contactor, Suppose if we are using star/delta operation. You would have a total 3 contactor with 1 timer. One contactor will be for star and other for delta. Star contactor is usually 1/4 size smaller than Delta one. The delay is introduce by timer. It's called switching delay.First the motor is operated on star which induces √3 times the voltage applied to motor winding. It will then take 40% more current than rated current. After few seconds it switched to delta contactor. It's like You put car in the first gear. Race it up, put the second gear. With motors upto 40HP, using Direct online is not recommended, the method that you have written in your text is called D.O.L. This things breaks motor coupling.

If you are taking about star/delta. Then you need to signal the star/delta timer module signal having interlock with the thermistor winding, because when overheat, you want your motor to shut down. You can take water level signal as an interlock too.

2) This means that resultant 252A of all phase, the motor can handle. This doesn't mean 252/3 = per phase.

3) There must be 6 terminals. You need to remove these copper strips. The picture shows you are using this motor in Delta configuration only.
The 6 points connects to the electrical star/delta. Red,yellow,blue wires attaches to the u1,v1,w1, remaining w1,u2,v2 goes to star and delta contactor.


W1 U2 V2
U1 V1 W1


4) Induction motor can offers an earth wire, no neutral wire in terminal box.

5) The two wires are of sensor known by PT100.You need to put this in interlock or else you cannot prevent it from burning away and also cannot stop it once overheated.


You must have some sort of Motor Control Center panel. Where you put all these things. Along with ampere meter, CT, phase indication, trip indication.

high guys Its been a situation for me and i need your help to drive 3 Phase,180 HP, Delta connection water pump.

I don't know the time frame for you to set these pumps in action. If this is a professional project with limited time, I would not recommended you to design the electrical system yourself. You can harm yourself or other in that.
I have done several projects professionally and I have previous electrical drawings as well. For your help I can upload some, but prior experience is required.I would still not recommend you to set this thing in action by yourself. You must also use phase sequence relay, voltage protection relay in your system. You also need to use auxillary blocks NC/NO along with your contactor, as they would be your feedbacks.

 

[Sajjadkhan]

ok now i know what star delta starter is and why is it necessary. i have searched alot and found that the motor labeled or symbolized as start/delta should run this way but my motor has only delta symbol. Is it ok to run it as star/delta or just delta.

start delta starters are expensive than magnetic contactors. so if i run it directly on delta what would be the consequences or will there be none?

 

[srizbf]

a motor of 180hp cannot be connected in delta at startup.
a veryhigh starting current and possible damage to the power line to the motor and to the motor also may happen.

a star delta starter is the simplest one .(even though you have exotic electronic controller to avoid the inrush current) . star delta is also less costly compared to other types of starting for 180hp.

as said in an earlier post , magnetic contactors internally form the stardelta starters.

may be , advised to choose proper method before venturing into 180hp experiment.

 

[chuckey]

Sajjadkhan
A star/delta contactor costs peanuts compared to the cost of the motor and the possibility of damage to life and limb. By asking all these questions I don't think you know enough about motors to be able to bring this project to a safe and successful conclusion.
What about speaking to the person who ordered the motor, he must have had some electrical design experience or failing that, phone up Siemans, I am sure they will be able to sell you some thing that will work properly.
Frank

 

[Sajjadkhan]

Actually i am convinced that it should be run in star mode for developing enough torque and then switch to delta mode as star mode is inefficient and damages the motor for long run. I was just asking because of this manual for my motor: it says that it can be run in both mode. i am just concern that running in delta mode may draw more current from the line and over loads the transformer. As there are 9 motors so there will be 9 step down transformer(1100 -->220v) for each motor but similar line.
http://www.siemens.com.pk/pdf/Operational instructions.pdf
One more thing, what should be the time delay to switch over from star to delta?

 

[Tipu606]

A 180HP 3 phase motor is always sold with a matching star-delta starter in a metal box with all motor protection inside
you only need to connect the cables to the power supply and check direction of rotation is OK or not ,if direction not OK interchange any two line leads to the motor starter
Rated current will flow in all three phases equally
the pump motor will run in delta after running approx for 30 sec to 45 sec in star
You ask the supplier of this motor where is the starter controller box?

 

[umery2k75]

@Chuckey

I don't think you know enough about motors to be able to bring this project to a safe and successful conclusion.

I agree with your point of view.

I am just concern that running in delta mode may draw more current from the line and over loads the transformer.

Running in star would cause it to overheat in the long run, as it would be taking under root three times more current per phase compared to delta. I have never seen design that runs motors in star for long.

As there are 9 motors so there will be 9 step down transformer(1100 -->220v) for each motor but similar line

In a length of 34Km, you are putting away 9 transformers(delta to wye), what about the High tension cables, 9 Transformers, Expensive HT switch gear trolleys, bus couplers, Vacuum Circuit Breakers from companes like Siemens cost in millons. I don't know the project layout, cost feasilbilty for putting away 9 HT transformers. Has this been consulted with any experienced designer? Is your decision, planning has final impact on the approval, modification of this 34km long project? What is your role within all this?

 

[Sajjadkhan]

Running in star would cause it to overheat in the long run, as it would be taking under root three times more current per phase compared to delta. I have never seen design that runs motors in star for long.

i didn't say that. I said running motor initally i.e. starting in delta mode is dangerous because the torque is low and if there is a heavy load then motor may not move, in that case there will be no back emf and only thing left is the winding resistance which will heat up and burn.

In a length of 34Km, you are putting away 9 transformers(delta to wye), what about the High tension cables, 9 Transformers, Expensive HT switch gear trolleys, bus couplers, Vacuum Circuit Breakers from companes like Siemens cost in millons. I don't know the project layout, cost feasilbilty for putting away 9 HT transformers. Has this been consulted with any experienced designer? Is your decision, planning has final impact on the approval, modification of this 34km long project? What is your role within all this?

these 9 water pumps are 1000feet apart in a line and will supply water to 2 water tanks which are 34 km far and are 500000 gal each.

I have the required idea now and i am using 3 magnetic contactors like this
Contactors and Control Circuits
Timing and temperature will be controlled via pic.

Now the only thing left is that thermistor yes its a thermistor and not a RTD like pt-100. i wonder where can i get its temperature curve. is it NTC or PTC.