Star-Delta Starter

[Platootod]

Addition : Beware when use plc control

May I add more information :
In some project ,If you use PLC control Star-Delta circuit
please protecttion both with hardwire and program (ladder)too.
because of plc run faster than Relay or contactor ,
So ,you need to add more timer in ladder to make sure Star is stop before run Delta ..(Please interlock between Star and Delta contactor with NC contacts at Output of plc (Hardwire) .(You can use Mechanical interlock device too)

From Picture :
Input X1 = Overload
X2 = Sw.Stop
X3 = Sw.Start
Output
Y1 = Main contactor
Y2 = Star contactor
Y3 = Delta contactor
T1 = Timer for stop Star contactor
T2 = Timer for Start Run contactor
Please check an appropriate time for your's job

 

[seppoalanen]

As you see, too many words for simple animal, please use VFDs !

 

[Platootod]

What do you think about this picture?

Here is some philosophy from this picture
We can think in difference way ..
By experiences
By ages
By relative
and etc...
What do you think about this picture...
Sure ..from all of us ..will not think the same....

 

[JohnW]

Star Delta starters

Be careful if you have 3 contactors, if you have 9 terminals in your motor you have a "Dhalander" wound star delta starter with high/low speed. I have some here and they do not work like a normal star-delta starter, sorry I connot tell you more than that. Anyone know more about this system?

 

[SLaubach]

Re: What do you think about this picture?

Not sure whats up with that picture, should i be seing something special?

Here is some philosophy from this picture
We can think in difference way ..
By experiences
By ages
By relative
and etc...
What do you think about this picture...
Sure ..from all of us ..will not think the same....

 

[Lancie1]

Goody,
I am glad that you mentioned about having the motor leads hanging out with no numbers and no way to tell which is which. That happens a lot - it seems that electricians like to just snip off the leads when pulling motor, instead of disconnecting them. Many times the wire numbers will get cut off also, or worn off from hard use.

I had a customer that requested a PLC device to determine which motor lead is which number. At first I thought this would be an IMPOSSIBLE job, but one day the proverbial light bulb went off, and I found a way, using only a Automation Direct DL-205 with ONE analog voltage input and some on/off inputs and outputs. The customer retired and sold his share of the business before I got it finished, but it seems to find all 9 exact leads of a 9 lead, 3-phase motor, every time. There are about 64,000 combinations! You may see this motor tester at http://www.forsytheandlong.com/.. Anyone interested in details?

 

[Eric Nelson]

Identifying motor leads...

There is also a chapter in "The Electrician's Book of Trade Secrets" (LINK) that details how to identify the leads of a 9 lead motor (wye connected motors only though). It basically describes how to locate the 3 wires on the star point, then determine the function of the remaining 6 wires with simple voltage tests.

I don't know how well this works, as I've never needed to try it (yet!)...

-Eric

 

[DickDV]

Most motors I've seen have the lead ID written on the lead insulation as well as on a tag. For those that don't have this, the test equipment above sounds really useful

 

[rsdoran]

I do believe I have seen this info somewhere

http://www.patchn.com/tutr-mot.htm

Note: Disconnect all wiring to the motor and the motor leads before taking any measurements, otherwise your readings may back feed through the rest of the machine wiring and give inaccurate results.

Identify an unknown motor
For example, You have a Three Phase Dual Voltage (240/480 vac) motor and there is not a wiring diagram attached. Disconnect all leads and measure continuity through the windings. Compare your findings with the "Y" connection diagram and the "Delta" connection diagram to determine winding style. A "Y" connected motor will have continuity through wires 7-8-9, a "Delta" motor will have continuity through wires 7-5-2. Look at the pictures and you'll see the difference.

Verify a motor is damaged or not
If you know the motor is "Y" or "Delta" connected use a multi-meter to measure continuity through the windings. A "Y" motor should have continuity through wires 1 and 4, 2 and 5, 3 and 6, and through 7 to 8 to 9. If there is not continuity through any of the wiring sets then you have an open winding, and the motor is bad. Use the "Delta" drawing for motors wired with a "Delta" connection, following the example of "Y" for lead continuity. Also verify each winding set has NO continuity to ground, if any winding has continuity to ground then the winding is shorted to ground, and the motor is bad.

Switch voltages from high to low or back
If a High/Low voltage wiring connection plate is not attached to the motor you can use the tables above to switch voltages. Make sure you know if the motor is "Y" or "Delta" connected or motor damage will result.

 

[Eric Nelson]

I was pretty sure you had that on your site, Ron... :nodi:

I was going to post a link, but couldn't find it. I was actually ON that page, but didn't scroll down far enough to see it...

beerchug

-Eric

 

[Norbert J. Gallagher]

wye delta starters

I have worked on some German equipment that used three Siemens contactors, which drove a 100 kW motor. The third contactor was used for plugging or braking the motor. It was wired like a reversing starter and there were resistors connected in series with the motor conductors. When the operator wanted to stop the amchine, the third contactor was employed and the braking load was dissipated through the resistors. It was a pretty neat set up. If the motor had built up to 1800 RPM's and the stop button pressed, it would really squeal.

We never let the smoke out of it though.

 

[seppoalanen]

Stopping by reversing with resistor could make mistake and motor really reversing. One way is use DC-voltage for braking. Old welding maschine is very good for big motors, there are 60 to 100VDC.

 

[Lancie1]

Eric Nelson,

I unfortunatley have had the problem of a motor with no readable numbers on the leads, many times. Many larger motors have only one metal band marker around the each lead, and this gets cut off when the motor is moved. Yes it is straight forward to find if you limit it to Wye type only, meaning your motor is still in place, maybe still connected. What if it is laying in the shop, with 9 unidentified leads hanging out, with no clue as to what any of the leads are? That is a little more difficult problem. It takes more than an ohmmeter to solve this one in any practical time frame. I will go ahead and tell the secret: If you apply 6 volts AC across one coil winding (you first have to find each coil pair), then the induced voltage in the complementary (closest winding) of the other coil group will be larger than the induced voltage in the other two windings! So you have to apply voltage to each set of 6 windings and measure the voltage between the other 7 wires, then repeat several thousand times until you find the correct combinations. This is difficult to do by hand, but with a PLC, it takes only about 2 minutes!

 

[Platootod]

Dear SLaubach
From this question ..You can see the answer in several way.
(a lot of dif. answer with the same question) It look like when we saw the picture that I have post . We can think in difference way too. (Only some point of view)
I will inform to admin of this Web Site to erase my second one in
later soon.
(The picture that I have post receive from siminar in Mechatronics system technology at...NYP Singapore)
No any serious...

 

[Platootod]

Could anybody give me some suggestion

There is some circuit using Start Star - Run Delta together with Softstart (Motor 75 Kw) ..(Power circuit below)
May be can explore the idia for some project.
Could anybody give me some suggestion about this Power circuit please
How to calculate or select an appropriate Magnetic Contactor?
(2 type of magnetic contactor)
What is the difference between type 1 and type 2 of magnetic Contactor
How to calculate or select an appropriate overload relay?
K6 in this picture is essential or not?
(someone told me using for good protection.
Some circuit from some book use 3 overload (add more below main cB)
1. Without Softstart K1 + K2 +K3 + K4
K1 + K2 = MAIN CONTACTOR
K3 = STAR CONTACTOR
K4 = DELTA CONTACTOR
2. With Softstart
K2 + K4 + K5 + K6 on at the same time ( K1 & K3 OFF )


Thank you very much