
MV soft starters
#1
Posted 27 April 2002 - 09:29 PM
Mark Empson | administrator
Skype Contact = markempson | phone +64 274 363 067
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#2
Posted 11 March 2003 - 12:45 PM
#3
Posted 11 March 2003 - 01:57 PM
Rockwell Automation, Benshaw, Saftronics, etc. All have web site data.
#4
Posted 12 March 2003 - 06:16 AM
Better thyristor designs and higher production volume have allowed cost reductions to the point where MVRVSS starters are now competitive with Autotransformer starters in all but the smallest size (100A and under). Although the product has been around since 1969, it wasn't until this recent economy of scale that they have been taken notice of. Many users are attracted to the concept by observing VFD technology, but are frightened by the extreme costs of MVVFDs. If the engineers become aware of MVRVSS starters as an alternative, albeit fixed speed, they try to find ways to fit them into operating schemes because they are typically 1/8th to 1/10th the cost of an equivalent VFD. Many large scale water projects are now using one or two MVVFDs backed up by several MVRVSS starters as a way of stretching the budget.
For what it's worth, Saftronics has backed off on Medium Voltage starters. They were brand labeling a product made by a small company in Los Angeles that apparently did little testing and had a lot of costly problems in the field.
#5
Posted 17 March 2003 - 05:55 AM
Until recently Solcon were brand labelling for ABB & Siemens however those relationships appear to have disolved for whatever reason.
Those manufacturers best recognised on the global market (in no particular order) are Motortronics, Benshaw and Rockwell. These products are distribued by numerous suppliers globally either under the OEM brand or a brand labelled version thereof.
In addition I am aware of one or two manufacturers (who have traditionally specialised in the low voltage market) that are moving to develop an MV range of products for near future release. Names will of-course be provided when they are ready to go to market.
Regards,
GGOSS
#6
Posted 18 March 2003 - 12:18 PM
#7
Posted 19 May 2003 - 06:16 AM
The company name for the Italian manufacturer of MV soft starters mentioned in my post of 17/3/03 is EEI (Equipaggiamenti Elettronici Industriali S.r.l.). However as they are no longer showing MV products on their web site I am unable to comment as to their present and future plans with such products.
Anyone interested in pursuing this further should feel free to contact EEI directly. Contact details (phone/fax/email etc) are available via the EEI web site.
http://www.eei.it
Regards,
GGOSS
#8
Posted 01 September 2003 - 01:02 PM
#9
Posted 04 September 2003 - 04:31 PM
#10
Posted 05 September 2003 - 11:57 AM


#11
Posted 05 September 2003 - 05:25 PM

#12
Posted 22 November 2003 - 12:17 AM
#13
Posted 25 November 2003 - 09:34 AM
I have also seen these referred to in a number of documents/manuals, and llikewise, I have not seen a good explanation for this.
My understanding is that the line reactors are added in some installations to reduce the rate of rise of current through the SCRs when the load has a capacitive element. It would apear that the cable capacitance for a long cable is of particular concern.
When we go from a low voltage (400V) installation to a medium voltage installation (> 10 x voltage) we have a much more significant charging current to charge the spurious capacitance of the circuit. At low voltage, this is not significant, but at medium voltage, this can become significant. If the rate of rise of current, and energy is too high, the SCRs can be damaged.
I would not personally be prepared to quantify these values at this time.
Best regards,
Mark Empson | administrator
Skype Contact = markempson | phone +64 274 363 067
LMPForum | Power Factor | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | Pressure Transducers | Smart Relay | GSM Control | Mark Empson Website | AuCom | Soft Starters
#14
Posted 26 November 2003 - 02:42 AM
Just FYI, I also found this paper that was presented by an IEEE member at the Power Systems World Conference in Chicago IL on Oct. 31, 2002. Wow is it ever filled with good info regarding MV SCR power switching!
http://www.enerpro-i...lt/scrsfire.pdf
#15
Posted 26 November 2003 - 03:51 AM
I've just completed reading the first one and a half pages and my head hurts! That normally means one of two things;
a. it contains quality information
b. it contains a lot of bs (no disrespect to the author, I'm just making a joke)
Will comment further once I've finished reading the remaining 11.5 pages ie sometime around January 2004.
Regards,
GGOSS
#16
Guest__*
Posted 20 October 2004 - 07:36 AM
#17
Posted 20 October 2004 - 06:32 PM
Mark Empson | administrator
Skype Contact = markempson | phone +64 274 363 067
LMPForum | Power Factor | L M Photonics Ltd | Empson family | Advanced Motor Control Ltd | Pressure Transducers | Smart Relay | GSM Control | Mark Empson Website | AuCom | Soft Starters
#18
Posted 10 November 2004 - 07:06 AM
Not sure if they make MV soft starter. I heard their LV soft starter are sold at very low price, for 7.5kW (c/w built-in by-pass) sell for only about USD80.
In fact, can anyone tell me if external by-pass contactor a MUST in a soft-starter controlled system? For instance, fan & pump or compressor applications?
#19
Posted 08 January 2005 - 12:04 AM
If you are comfortable with using a vented enclosure, you probably don't need a bypass contactor, but keep in mind that with cooling air comes dust, moisture and corrosive contaminants.
Edit: Since this is the Medium Voltage forum I should add that the heat loss is PER SCR, so in MV systems where SCRs are in series strings, the watts loss is even greater. Bypass contactors are ALWAYS included in MV RVSS starters now.
#20
Posted 20 October 2006 - 10:31 AM
There is a company in India (Pune to be precise) which also manufactures MV Soft starters. However, these starters do not use thyristor switching, instead they work on FCMA principle (Flux Compensated Magnetic Amplifier). The technology may sound obsolete, but I can assure you that there are many takers of such starters in India. And if I am not mistaken, they have recently supplied these starters as far away as Jamaica. Link to their site is given below. In India, they have acquired a good share of the MV soft starter market as their price is 1/3rd of an equivalent thyristorized soft starter.
FCMA
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