Product category:
Industrial Drives/Controls
News Release from: REO (UK) | Subject: SAG M soft start units
Edited by the Engineeringtalk Editorial
Team on 25 December 2000
Soft starters improve 3-phase AC motor
efficiency
The new SAG M microprocessor controlled soft start units from REO are designed for 3-phase AC motors and include features which improve the efficiency and overall cost effectiveness of the unit.
The new SAG M microprocessor controlled soft start units from REO are designed for 3-phase AC motors and include features which improve the efficiency and overall cost effectiveness of the unit Most 3-phase motors are supplied with a 6-wire connection for use with star/delta starters
This article was originally published on Engineeringtalk on 25 Apr 2008 at 8.00am (UK)
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The current drawn in delta connection is the reciprocal of v3 (root 3) of the star connected current (i.e divided by 1.732) and the new SAG M soft start units have been designed to take advantage of this to operate with a so-called open delta connection.
However, if desired, the same controller will also run a 3-wire star connected motor.
When the 3-wire connection is used, SAG M enables the full rated current to be conducted across the semiconductors.
The 6-wire connection, producing v3 times the rated current, allows the use of lower rated components and smaller heatsinks.
Alternatively, a higher unit capacity produces a motor supply power increase of v3 times.
In either case the unit offers a highly economic solution.
During the start up phase, the current is limited.
This reduces supply voltage dips and therefore allows lower rated protection devices and smaller cabling to be used.
When the top of the start up ramp is reached, the thyristors fire on full conduction (zero degree firing angle) which eliminates the need for a by-pass contactor.
In cases involving higher current ratings, this represents very significant savings which approach 50% of the price of a conventional soft start.
All functions are set through the simple to use, digital front panel and the units are CE approved. Request a free brochure from REO (UK) ...
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