Circuit interrupter having controlled rate of arc extinguishment

In a circuit interrupter comprising a pair of detachable contacts, and means for puffing the arc between the contacts including an arc extinct chamber filled with a fluid for arc extinction which is pressurized by the arc formed between the contacts when they are disengaged, said pair of detachable contacts being at least one movable contact and at least one fixed contact;

• an improvement which comprises control means including a control device for controlling a departing speed of the movable contact after disengagement from said fixed contact in at least two steps and said control means further including at least two springs exerting force against said control device to force the movable contact mounted thereon out of engagement with the fixed contact at an accelerated rate;
• said at least two springs driving the movable contact until the movable contact is located a specified distance from the fixed contact;
• one of said at least two springs ceasing to work against said movable contact at this point and causing a reduction in the accelerated rate of disengagement to prevent rapid extension of the arc and thereby prevent excess arc energy from forming in the arc space between the movable contact and the fixed contact and to prevent the fluid from reaching an elevated temperature;
• the other of said at least two springs continuing the opening movement of the movable contact out of said arc extinct chamber at a decelerated rate to thereafter puff the pressurized fluid in the arc extinct chamber which is pressurized by the arc formed between the movable contact and the fixed contact to thereby control arc extinguishment by controlling the departing speed of the movable contact.