Soft Starter and Delta Starter

You can use whatever starter you want, consistent with the motor, the power source feeding it, what it's being asked to do, and the type of loading. I am assuming that you're not using both simultaneously.

I will use both simultaneously. Does it create any problem? First soft starter and then Delta starter.

This is nonsense. Explain why, please, so I can understand.

The pump itself has Delta starter , and we will Supply energy to pump panel with soft starter. There is no reason. Do you think we need to remove one of them or keep both.

I think you need to decide why you want to change the mode of starting and explain it to me.

We bought a new pump . New pump includes Delta starter. We thought need also soft starter as the old one. But from your comments I understand that we do not need it. Anyway, we will use both. Does it work with both soft starter and Delta starter? I want to thank you for your quick responses.

The method of starting depends upon the wiring, which you have said nothing about. Do you have a qualified Electrical Engineer over there or are you lot a load of DIY-ers?

We do not have electrical Engineer. But I will request help about wiring.

So how do you expect to size the cables feeding it? How do you intend to provide overload protection facilities? Does the motor have an anti condensation heater? Or a thermistor? How will you design a starter for it? Where will you place it? I don't even know what this pump is pumping yet!

Do yourself a favour. Hire someone locally, appropriately qualified, to sort this one out using your national standards, and cease asking strangers over the internet to do it for nothing. A pump that size is hardly a battery-powered toy.

This is my stop. I'm off. Good luck.

Contact the pump manufacturer for advice and get a qualified electrician to install the pump.

A 160kW pump is not a toy and there is no guarantee the replacement has the same wiring and control as the old one. Also, I am not sure if running the two soft start systems in series is even safe.

Seems redundant. A softstarter is better than a star-delta starter, and only one is required. i would bypass the star-delta starter and start the motor through the softstarter. In fact you can remove the star-delta starter and use it elsewhere or even sell it

In star-delta(wye-delta)starting due to changeover transient, the motor,the driven machine, the coupling between the two etc will undergo severe mechanical stress as well as stator winding should withstand severe electrical stress.

What you are describing is a soft starter (or alternatively a VFD) with a bypass contactor (delta) when the motor attains near-synchronous speed. The bypass contactor eliminates some small losses that the soft starter or VFD will have. Such an arrangement is fairly common if the motor normally runs at "full" speed.

Yes.

You can parallel the soft-starter with the delta starter using the soft-starter for starting the pump and getting it up to speed then transfer to direct-across-the-line motor feed by closing the delta starter and opening the soft-starter.

This will save wear & tear on the soft-starter as well as the pump motor.

I would not attempt to connect the two starters in series.

Most soft-starters are rated for continuous use and do not require a bypass contactor/starter however not knowing what you have I would suggest you contact the manufacturer of the soft-starter if you have any questions.

Be safe and good luck.

If the "delta" starter you mention gets it's control power (to include the contactor coil) from the line, how would it react to the output of a soft starter?

An off topic hit by a P.O.S.

How is what I asked off topic?

You should try to drive the DOL starter with a soft start and watch the reaction of the contactor in the DOL starter as it tries to pull in against the other-than-60 or 50 Hz current it was designed for. Salami Balony!

No, a soft starter does not change the frequency, just the RMS voltage. However, you still cannot power anything (other than a motor) from the output side of a soft starter, or any other reduced voltage starter or VFD for that matter.

So, as far as the contactor coil is concerned, am I on or off topic?

If you were to feed the contactor coil power from down stream of a soft starter, it would do nothing until the voltage from the soft starter increases to the minimum value that makes the armature pull in, that's all. So you are sort of in the middle on that.

Increase to the minimum value, pull in, drop out on inrush, pull in, drop out, repeat. Plus no load or reference for the soft start until pull in.

There seems to be some confusion here.

First off, you keep saying "delta starter". There is no such thing. There is a DOL (Direct On Line) starter, and there is a "Star-Delta" starter that is used for controlling starting current (or at least appearing to). Most people here are assuming that when you are saying "Delta starter" that you are meaning "Star-Delta" starter, especially since this is for a 160kW motor. I will assume so as well, but be aware of the mistake you are making and the effect it may have on what you are being told.

Star-Delta is what is called a Reduced Voltage Starter, meaning that it effectively reduced the voltage getting to the motor, which reduces the current it takes when starting, but also reduces the torque that the motor produces. In many cases, the motor initial torque during starting is greater than the load requires, so reducing the voltage to reduce the negative effects of high starting current is acceptable. A "Soft Starter" is usually referring to a "Solid State Reduced Voltage Starter", which does exactly the same thing, however it does it better.

So because BOTH devices are designed to reduce the voltage to the motor, there is NO WAY that you will be able to use them BOTH in series with each other! That concept makes ABSOLUTELY NO SENSE WHATSOEVER!!! Don't do it. Not only will your motor fail to start because you will reduce the voltage so much that it generates far too LITTLE torque but it is highly likely, if not assured, that the Star-Delta starter switching will DESTROY the solid state components in the soft starter in a matter of seconds!

What Tornado and SHOCKISCAN have mentioned is putting the Star-Delta starter in PARALLEL with each other. The concept here is that because the Solid State devices produce some heat, when the ramping process is complete and they are no longer needed, you can eliminate the heat they give off by bypassing them using a DOL starter. but it is a VERY BAD IDEA to use a Star-Delta starter as the bypass for a solid state soft starter. As mentioned earlier, the transition from Star to Delta involves creating a very severe spike of current and sometimes voltage. That spike can damage the solid state components in the soft starter even if wired in parallel with it, not just in line with it. So do NOT do that either.

many solid state soft starters are already including a bypass contactor in their design now, so it is entirely possible that you need do nothing else. The solid state soft starter is a far far superior way to accomplish reduced voltage starting compared to Star-Delta, I would eliminate the Star Delta scheme. But that will involve re-wiring your motor if it came to you with the Star-Delta starter already wired. Engage the services of a qualified and experienced electrician to do this properly.