Founded in 1983, GridStone Electric specialize in auto voltage optimizers and transformers.  As the first manufacturer of auto voltage optimizers in China, GridStone have installed tens of thousands installations later. The products range cover servo motor voltage optimizer, SCR control voltage optimizer, IGBT control frequency and voltage optimizer, LV and HV transformer and reactor.  Thanks to over 30 years in the business and on going technical research, GridStone have become a competitive high-tech company, and meet the requirements of a constantly growing number of customers through design, production and service. 
Besides standard production, GridStone are flexible  and strong at custom design and production according to the customers' specification. Expert training and technical support are provided to serve the customers quickly and professionally. 
With GridStone products, the customers can cut electric costs and reduce carbon output, have less equipment maintenance and extend equipment life, no matter where their facility is located on a utility line. 
GridStone factories are ISO9001 certified with strict quality control procedure, and provide standard warranty 2 years (5 years, extendable to 10 years for Australia and UK) .  

Our History
1983,  GridStone factory for AVR with servo motor was started and the first AVR with servo motor was successfully built in China. 
1985.  factory for transformer was started 
1998.  New office and factory of AVR were started in Shanghai, China. 
2002.  The first AVR controlled by SCR was released, and massive production started at end of the year.
2005.  GridStone was invited and joined the China Power Supply Association.  
2008.  Brand name "Shanghai Voltage Regulator" was started in China.
2009.  New type AVR with SCR was released.  More fast, more reliable and more intelligent. 
2010.  The first frequency and voltage regulator with IGBT control is released. 
2013.  12pcs AVR with SCR were installed in Australia, and have been working well since then. 
2014.  New factory for transformer was started. 
2016.  GridStone brand name is started for all AVR and Transformers to be used in global market.