Importance of correct compensation
1. For short circuit compensation all windings that are used in a program must be shorted. This should be done with a solid wire connected to Kelvin clips for both power and sense connections on each node. For simplicity where parasitic effects may not be significant, all nodes used in a program may be shorted together. However, for the most accurate compensation it is recommended that nodes used for each winding be shorted independently.
2. For open circuit compensation all nodes should be left open
3. Compensation should be run after the program is downloaded and repeated every time a program change is made
4. Please make sure that all Kelvin connections to the fixture are secure, also that Kelvin jaws are clean and not damaged
Please find two attachments entitled “Shorting methods for short circuit compensation” and an AT test program called “compensation.atp” found in the zip file called "Compensation".
In this test program there is an inductance test for primary and secondary and a leakage inductance test with the primary as the energized winding. The LL test shows a test limit of 20nH, a low value of leakage inductance. For the LL test especially, if all nodes were shorted together parasitic effects of nodes 17 and 19 may affect secondary compensation of nodes 18 and 20, all being connected together. However if 17 and 19 are shorted independently of 18 and 20 this parasitic effect will not be present. For higher values of leakage inductance this parasitic effect may not be as dominant and shorting all nodes together may be acceptable. This same argument will also apply to inductance tests in this program, especially if inductance is a low value.
Also, other sensitive tests such a RESP and C (frequency response and interwinding capacitance) may be sensitive to the method of compensation.