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Resolver Wiring; Colors & Functions

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If you ever plan to replace or test a resolver then you need to know the functions of each wire.  This can be very difficult to determine with out a little knowledge and a voltmeter.  There is an industry standard for resolver wire colors that most manufacturers choose to use.  These colors are as follows;
Wire Color Wire Function
 Red/White  Excitation +
 Black/White  Excitation -
 Red  Cos +
 Black  Cos -
 Yellow  Sin +
 Blue  Sin -
Sometimes Yellow/White can be used in the place of Black/White for Excitation-.  These are industry standard wire colors but you will come across other brands of resolvers with their own proprietary color designations.  When this happens you will need to use a voltmeter to assist you in determining wire color versus function.Almost all resolvers have 6 leads.  Use a voltmeter to ring out the leads and determine which 3 pairs of wire are circuits.  Then record the resistance of each circuit.  The Cos and Sin circuit will have the same resistance, so the circuit with the different resistance will be your excitation circuit.  If any circuits ring open, or all three circuits have different resistances then your resolver could have a damaged winding and need to be replaced/rebuilt.These are some basic tips on how to determine a resolvers wiring.  In order to continue on and designate exact wire functions on nonstandard wire colors you will need to excite the windings with the proper frequency and use an oscilloscope.

Comments

"In order to continue on and designate exact wire functions on nonstandard wire colors you will need to excite the windings with the proper frequency and use an oscilloscope"  
 
How i can use a scope to test a resolver? 
 
How i can excite the windings??
Posted @ Tuesday, March 16, 2010 12:17 AM by Ivan Dario Arrubla
Before you can determine exact functions of your resolver wires you will need background information concerning the type of output your motor drive or controller is looking for. Most manuals will describe the specific sin and cos outputs used based on the direction rotation. You need this information to proceed. 
 
In order to test your resolver you will need to excite your resolver with the proper voltage and frequency which is typically written on the resolver label. Most resolvers are between 4-6V at 3-10KHz. People who don't have test equipment that can feed high frequency hook their resolvers to their drive and check the sin and cos outputs either on the drives test points or directly off of the resolver. 
 
Once you have the resolver running on the scope you just need to set up the outputs of the resolver to match the drive/controllers specifications paying attention to the direction of rotation. 
 
Here are some links with some more information on resolver windings: 
 
<a>http://www.controlsciences.com/resolver_application_data.shtml 
 
<a>http://www.amci.com/tutorials/tutorials-what-is-resolver.asp 
 
Posted @ Thursday, March 18, 2010 9:08 AM by Jared Stearns
hi.does the mechanical position of a resolver matter when fitting to a servo motor? i notice the resolver stator is not fixed to set position.. any info would help alot..
Posted @ Thursday, May 20, 2010 1:59 PM by dermot murphy
Dermot, The angular position of the resolver stator to the resolver rotor is critical. Most resolver stators are mounted in a way that they can be rotated 360 degrees easily in relation to the motor housing with no alignment pin or key. When the resolver stator or rotor is rotated independent of the other, however, the electrical angle of the resolver relative to the servo motor will change and you will lose your proper alignment.  
 
You can rotate the entire resolver as a unit to any physical position relative to the motor. Many resolver manufacturers mark a line from the rotor to the stator to designate 0 degrees. As long as the lines line up you can put the resolver in any position you like and know your resolver is at 0 electrical degrees. 
 
Hope this Helps!
Posted @ Thursday, May 20, 2010 2:32 PM by Jared Stearns
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