| 摘要 |
The shunt connected field winding is provided with a free wheel diode and also a series diode. The field strength is indirectly controlled by the mark-space ratio of the DC supply to the motor as in 1563981. The control is made more accurate by incorporating direct measurement of field and armature current, and by using the ratio of these quantities as a control quantity. The required armature current is set by a diode maximum current circuit and a constant value which is fed to a summing junction together with the actual armature current. The latter is also fed to a second junction together with the actual field current. Junction outputs go to regulating amplifiers with stabilisers, and the higher of the two outputs used to control the DC regulating circuit in the appropriate manner. |
