ECLIPSING BINARIES WITH CANDIDATE CP STARS .1. PARAMETERS OF THE SYSTEMS HD-143654, HD-184035 AND HD-185257

Lightcurves of three eclipsing binaries (I-ID 143654 = TV Nor, HD 1840 35 = HR 7422 and HD 185257 = HR 7464) in seven colours are analyzed an d their photometric elements are given. Published radial velocities of two of them allow some constraints to be put on the masses of the com ponents, while new radial velocities allow us to estimate the mass and absolute radius of each component of the system TV Nor. There seems t o be no Ap star in this system, in spite of its EuCrSr classification in the Michigan catalogue. The position of each component of TV Nor in the HR diagram is in excellent agreement with stellar evolution model s having Z = 0.020 and an age t = 2.51 x 10(8) years. There is an Am s tar in the system HD 185257, but no CP star in the system HD 184035 in spite of its sharp lines. The physical parameters of these two binari es could be determined, but less accurately and in a less fundamental way than those of TV Nor. They match theoretical isochrones and evolut ionary tracks in a satisfactory way for I-ID 185257, but the measured mass function of HD 184035 seems slightly too small compared with the expected theoretical masses. More data, both photometric and spectrosc opic, would be useful, especially for the last two systems.