| 摘要 |
PURPOSE: A device for preventing a defect is provided to prevent a defect of a current driving device by an over current by automatically cutting a flow of over current from an input power to the current driving device and by displaying a mis operation by the over current to a user with detecting a size of current fed from the current driving device such as a stepping motor. CONSTITUTION: When a current of an input power is fed to a stepping motor(110) and a comparator through a switch(120), the comparator(130) outputs a compared result to a checking unit of over current (150) by comparing a size of a previously established standard current with the current fed through the switch(120). The comparator(130) outputs a low level signal if the standard current is larger than the current of input power, and outputs a high level signal if the standard current is smaller than the current of input power. When the high level signal is transferred from the comparator(130) over an established standard time through an establishing unit of time(140), the checking unit of over current (150) outputs a cutting signal of over current to a control unit of switching(160) and a microprocessor(180) for preventing a break of the stepping motor(110). When the cutting signal of over current is transferred, the control unit of switching(160) does not feed the current to the stepping motor(110) by turning off the switch(120), and a microprocessor(180) controls a display unit(170) after checking a stop of the stepping motor(110) according to the cut of current.
|
