Transient characteristics and reliable commutation limit of DC thyristor commutatorless motor

This paper presents an analytical method of the transient characteristics and the reliable commutation limit of DC thyristor commutatorless motor. An induced voltage constant of the commutatorless motor is affected by the over lapping angle and the armature reaction. In the present report, we proposed that the induced voltage constant can be treated as a linear function and the vari­ous kinds of transfer functions are given with the constants. Using these transfer functions, the transient performances of the over lapping angle and the allowable commutation angle etc. and the reliable commutation limits are examined. As a result, it is cleared that the effects of the ar­mature reaction and the over lapping angle to the induced voltage constant can be treated as a increase of the equivalent armature resistance and the reliable commu­tation limit is advanced by the large leading commutation angle, the large smoothing reactor, the large damper coefficient and the small mechanical time constant.