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Can I bypass the sofstarter 3RW40 by external contactor

Created by: alesnik at: 8/29/2008 9:43 AM (9 Replies)

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8/29/2008 9:43 AM	Rate (0)
alesnik Posts: 2 Rating: (0)	HI, I'd like to ask, if I can bypass the sofstarter 3RW40 by external contactor, when softstarter is internal bypassed and then I switch off the softsterter?. Would sofstarter turn off by error in this operation? Thanks for reply.
alesnik Posts: 2 Rating: (0)	Last edited by: CS Moderator at: 29.08.2008 15:49 new subject after importing to the conferences
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8/29/2008 4:25 PM	Rate (0)
Gascoigne Posts: 7 Rating: (0)	Yes. It's possible, but you should turn off the soft starter or take away the ON-command. But why using an external bypass contactor? There is already an integrated bypass contactor inside the 3RW40 soft starter. Regards, Gazza
Gascoigne Posts: 7 Rating: (0)	Last edited by: Gascoigne at: 8/29/2008 4:25 PM
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8/30/2008 10:55 AM	Rate (0)
Gebhardt Karl Platinum Member Joined: 7/16/2006 Last visit: 1/2/2024 Posts: 1502 Rating: (176)	>Yes. It's possible, but you should turn off the >soft starter or take away the ON-command. Remenber, ther is aditional an Time betwin ! ! ! >But why using an external bypass contactor? So far i know "YES" >There is already an integrated bypass contactor inside the 3RW40 soft starter. After Start, perhaps as exaple 5 second bypasst a contactor the the 3RW40. TIME: Start-ramp, Stop-Ramp When you plan bypassed extern --> as exaple after 5 second must be bypassed with extern conector. But you dont need this
	Karl
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8/31/2008 10:19 AM	Rate (0)
Ayman Elotaify Platinum Member Joined: 5/28/2008 Last visit: 11/6/2024 Posts: 4516 Rating: (839)	Dear All, Yes of corse you can bybass the softstarter after starting period finished!. Yes The softstarter 3RW40 has an internal contactor and this contactor is energized after the motor aquires its rated speed. Sometimes I use Only one softstarter for starting of many identical motors. These motors shouldn't start in the same time, and after each motor aquire its rated speed, a set of contactors will by bass it and the the power folow doesn't comes from the softstarter as it will be used to start another motor! It's a good way and cost effective if you have many identical motors but the disadvantage is that the wiring will not be such easy.
	Ayman Elotaify
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12/19/2008 9:15 AM	Rate (0)
alesnik Posts: 2 Rating: (0)	Hi, I need bypass the softstarter because of starting many motors, as describe Ayman Elotaify. The problem was in monitoring current, even when the internal contactor is closed. When the current falls under certain limit for a certain time, softstarter turn off by error. This monitoring isn't described in manual.My question is WHY? This error could occured, when I external bypass the softstarter and the part of the current flows throw the external contactor. So i tried to turn off softstarter imediately after axternal bypass so the error isn't evaluate. It looks correct. Thanks to all for advices. see: /tf/WW/en/Posts/17698#77949
alesnik Posts: 2 Rating: (0)	Last edited by: alesnik at: 12/19/2008 9:23 AM
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12/19/2008 11:54 AM	Rate (1)
Santoosh Posts: 22 Rating: (7)	Hi, Usually thyristors required minimum load when they are in operation. In the older version it is 18-19%. Now with the new version it is around 20% of the rated current of the thyristor or the setted current value.Any motor at the time of startinggives this value, but after ramp-up (internal contactor switched ON) if the load is decreased, then failure indication comes and trips (Device-green,Failure-red colour). There are three reasons in the manual for this : missing supply voltage,phase failure, no- load voltage. No - load voltage means no required minimum load current. This protection cannot be by-passed.
Santoosh Posts: 22 Rating: (7)
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12/22/2008 9:53 AM	Rate (1)
Ayman Elotaify Platinum Member Joined: 5/28/2008 Last visit: 11/6/2024 Posts: 4516 Rating: (839)	Hello, Let us immagin the follows: You have more than one motor and you want to start each of them using softstarter and you have only one softstarter. Then you will start the first one until it will aqquire its rated speed, then bypass it by an external contactor and disconnect the output of the softstarter from the first motor to connect it to the second motor. At the moment the softstarter being bypassed, an error will be generated to the softstarter due to current value became too low, Ack. is requested or you can solve it by disconnecting the incoming power of the softstarer (A1 & A2) terminals after disconnecting the output of softstarter from first motor. I do not recommend to switch the softstarter immediatly when bypassing it as it may make something like hunting in the motor! NB: We are still talking here on the 3RW40 series, and if we could go to 3RW44, Ack via profibus communication can be carried out Regards,
	Ayman Elotaify
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12/22/2008 10:14 AM	Rate (0)
Santoosh Posts: 22 Rating: (7)	Hi, This is a very good example for switching several motors by single SS. Also can any body explain about the acknowledge function in 3RW44
Santoosh Posts: 22 Rating: (7)
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12/22/2008 10:44 AM	Rate (0)
Ayman Elotaify Platinum Member Joined: 5/28/2008 Last visit: 11/6/2024 Posts: 4516 Rating: (839)	Hello, It's very easy to control 3RW44 softstarter via profibus. I have a manual of more than 5MB and if you are interested send me your e-mail address in a privite message to share it with you. Here also attached two screen shots that descripe how you can see I/Os of the SS using profibus and how could we read the error we are talking about. Regards, Attachment screen shots.zip (490 Downloads)
	Ayman Elotaify
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7/24/2017 9:56 AM	Rate (0)
Jen_Moderator Diamond Member Joined: 6/19/2017 Last visit: 9/6/2024 Posts: 8175 Rating: (172)	New question published by lelekulhbkjbjkkkkkkkkkkkkkkkkkvh is split to a separate thread with the subject How can the softstarter protect from overvoltage?. Best regards Jen_Moderator

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