Paul, Mine is not a standard test but see if it helps in your case. We use impedence analyser or certain LCR bridge (e.g. HP4284A) to measure the phase angle. In the AC phasor diagram, the DCR vector is at 0 deg, the XL vector is at 90deg, the XC vector is at -90deg. If the DCR is small, an inductive coil should have the phase angle close to 90deg. With the intra-winding capacitance, the angle will be dragged down. This simple principle may help you to calculate the exact capacitance. K.K. Chin Artesyn Technologies www.artesyn.com From: Paul Orlando <[log in to unmask]> AT NetMail on 08/18/98 11:30 AM EDT To: [log in to unmask] AT NetMail@ccmail2 cc: (bcc: KK Chin) Subject: [TN] Testing of transformer coils