Current never diveded between soft starter and bypass contactor ... All of it will passes through soft starter in start and stop time periods And all of it will pass through the bypass contactor in steady state period With my respect to you

@John-qr4kf

2 жыл бұрын

Well,i thought the current flow will tend to take the path with less resistance. In this case,when the soft start and the contactor are connected in parallel to the motor, which path will the current flow. I tend to think, the contactor has less resistance in comparison to the soft starter. The same principle applies when a person working on a grounded metallic part and it happens to have a short circuit, the cable connected to the metallic part will offer an alternative route of the current flow,other than the human body. What do you think my dear friend. I might be wrong.

@John-qr4kf

2 жыл бұрын

If you do your research, you will find out that ABB soft starters have an internally assembled bypass contactors. Therefore, one doesn't need to add any other contactor when using ABB soft starters.

When we use a line contactor, from where we could energize its coil through the softstarter? Could you please clarify that point? Because if we will use the output relay r3, it will be always opened?

@John-qr4kf

2 жыл бұрын

From my diagram,you can see that you can energize the bypass contactor, but not the line contactor.Because the line contactor is in series with the soft starter, so,i don't think it's possible to energize the line contactor through the soft starter.

@John-qr4kf

2 жыл бұрын

I have used relay 1 in my illustration because it's a fault contact,just to open the line contactor incase of a fault. Otherwise both the line contactor and the soft starters have to be energized together from an outer source.

@John-qr4kf

2 жыл бұрын

A line contactor is standing in the way of the supply from the soft starter reaching the motor, therefore, if the supply won't reach the motor as the contactor is open in its way,the soft starter will immediately indicate there isn't any load(motor),hence it will trip. If you have a different suggestion, just let me know.

@princessmaram5397

2 жыл бұрын

@@John-qr4kf In case of an occurance of a fault, how did the relay reacts to open the line contactor?

@John-qr4kf

2 жыл бұрын

@@princessmaram5397 relay 1 acts like an overload contact 95,96,which opens incase of an overload. In this case, relay 1 will open once there is an fault in the soft starter, and since you are energizing the contactor coil through that contactor, the line contactor will hence dis energize incase of a fault.

In the series of soft starter, the contactor is connected, when it is closed comment fault phf

Dear good afternoon. I have a doubt. Due to low voltage in CL1 and CL2. I get the CLF alarm. It is possible that only the Alistart 48 will be reset. To avoid having to go to the site to perform a reset. Thank you for your help. Greetings from Argentina.

@John-qr4kf

2 жыл бұрын

Thanks for your response. In other words,your problem is already solved. If that is the case,i am greatful too. Greetings from Dubai.

@silviovisca5117

2 жыл бұрын

@@John-qr4kf Dear Jhon, could you tell me what that solution is like ... I didn't understand where to look for it.

@John-qr4kf

2 жыл бұрын

In that case,it seems your voltage to cl1 and cl2 is surging. In that case get a tranformer with 2 phase primary supply(here in Dubai 400v). Your Secondary supply to cl1 and cl2 from the transformer (here in Dubai 220v). The main purpose of using a step down transformer to supply the soft starter control is to maintain the stable voltage, hence avoiding the voltage surge.

@John-qr4kf

2 жыл бұрын

In other words, try to maintain the control power supply to the soft starter,if it goes down by a certain percent thats why you are getting the alarm. But if you solve the control side,what about the power supply to the motor, won't the motor draw more current because of the sudden low volt supply.just food for thought.

@silviovisca5117

2 жыл бұрын

@@John-qr4kf Perfect Jhon. Very grateful to her response. Here in Argentina the voltage is 220V. The problems are frequent when there are drops of tension. I'll see maybe use a stabilizer.

So there's no other contactor beside bypass contactor?what about atar or delta contactor,do we need them?

@John-qr4kf

3 жыл бұрын

You can choose to have the line contactor which is in series with the soft starter. But why waste money for that. On the other hand,the bypss contactor is a choice,you can use it or choose not to.like i explained,its purpose is to help the soft starter when running the load,but not when starting. Why do you need the star delta when actually the soft starter came to replace the star delta. As the name suggests it starts the motor softly.and the purpose of the star delta is to start the motor,rather softly. Imagine a manual car,gear number 1star and delta connection is the next or highest gear,avoiding the higher starting torque if you were to use a single contactor. I hope i have answered your question.

@John-qr4kf

3 жыл бұрын

Though some soft starters nowadays are coming with an already internally installed bypass contactor.a good example is the ABB soft starters which have an internal contactor.

@John-qr4kf

3 жыл бұрын

But,if you are talking about a bypass to run the motor independently without a conjugation with the soft starter,then the star delta as a bypass can apply in such a case. An alternative of running the motor with the soft starter only or the star delta.

@kevinimation5508

3 жыл бұрын

@@John-qr4kf ok,then what about if we want to change the direction?like forward-reverse rotation of the motor?do we need forward-reverse contactor to combine it with the softstarter?

@John-qr4kf

3 жыл бұрын

@@kevinimation5508 definitely,the forward and reverse contactors have to be added in the equation.