Relay drive systems
A drive system for a switch can include a control module configured to control, directly or indirectly, a state of a switch between a first state and a second state. The drive system can also include a transition timing system configured to measure a transition time that the switch is in transit between the first state and the second state.
1 . A drive system for a switch, comprising:
a control module configured to control, via a control signal, a state of the switch between a first state and a second state;
a transition timing system configured to measure, via a timer module, a transition time that the switch is in transit between the first state and the second state; and
a health monitoring module configured to receive the transition time and to determine a wear condition of the switch based on the transition time.
2 . The drive system of claim 1 , further comprising:
a drive line operatively connected between a voltage supply and a contactor coil of the switch; and
a drive switch disposed on the drive line and operatively connected to the control module, wherein the drive switch is configured to pass a voltage from the voltage supply to the contactor coil of the switch in a closed state and to prevent the voltage from passing to the contactor coil in an open state.
3 . The drive system of claim 2 , further comprising:
a driver operatively connected to the control module and configured to drive, via the control signal, the drive switch between the open and closed states based on control signals from the control module.
4 . The drive system of claim 2 , wherein the transition timing system includes the timer module, and a voltage spike detector operatively connected to the drive line and configured to detect a voltage spike associated with a slowing or stopping of motion of an armature of the switch.
5 . The drive system of claim 4 , wherein:
the timer module is operatively connected to the control module and is configured to receive a start signal therefrom indicating a start of a transition between the first state and the second state,
the timer module is operatively connected to the voltage spike detector and is configured to receive a spike signal therefrom indicative of the voltage spike associated with a slowing or stopping of motion of the armature of the switch, and
the timer module is configured to output the transition time based on a difference of time between the start signal and the spike signal.
6 . The drive system of claim 5 , further comprising:
a blanking time module disposed between the voltage spike detector and the timer module,
wherein the blanking time module is operatively connected to the control module and is configured to receive the start signal therefrom indicating the start of the transition between the first state and the second state, and
wherein the blanking time module is configured to prevent a spike signal from passing to the timer module for a set blank time period of time after receiving the start signal to prevent transient voltage spikes from prematurely stopping the timer module.
7 . The drive system of claim 6 , wherein a blanking time period is at least an order of magnitude faster than a total transition time of the switch.
8 . The drive system of claim 7 , wherein the health monitoring module is configured to receive the transition time from the timer module and determine a wear condition of the switch.
9 . The drive system of claim 8 , wherein:
the control module is configured to output a cycle count with each cycle of the switch, and
the health monitoring module is configured to receive the cycle count and determine an estimate remaining life of the switch based on data including the cycle count.
10 . The drive system of claim 9 , wherein the health monitoring module is configured to determine an average transition time.
11 . The drive system of claim 10 , wherein, if the average transition time increases above an end of life threshold, the health monitoring module is configured to output an end of life signal.
12 . The drive system of claim 11 , wherein, if the average transition time increases above the end of life threshold and the cycle count is below an estimated cycle life total, the health monitoring module is configured to output a premature end of life signal indicating that the switch is failing before an expected cycle life total.
13 . The drive system of claim 10 , wherein, if the transition time increases above a failure threshold, the health monitoring module is configured to output a failure signal.
14 . The drive system of claim 1 , wherein:
the first state is an off state; and
the second state is an on state.
15 . The drive system of claim 1 , wherein:
the first state is an on state; and
the second state is an off state.
16 . A switch system, comprising:
a switch having a contactor coil and an armature; and
a drive system for driving the switch between a first state and a second state, the drive system comprising:
a control module configured to control, via a control signal, a state of the switch between the first state and the second state;
a transition timing system configured to measure, via a timer module, a transition time that the switch is in transit between the first state and the second state; and
a health monitoring module configured to receive the transition time and to determine a wear condition of the switch based on the transition time.
17 . The switch system of claim 16 , further comprising:
a drive line operatively connected between a voltage supply and a contactor coil of the switch; and
a drive switch disposed on the drive line and operatively connected to the control module, wherein the drive switch is configured to pass a voltage from the voltage supply to the contactor coil of the switch in a closed state and to prevent the voltage from passing to the contactor coil in an open state.
18 . A method, comprising:
measuring, via a transition timer, a transition time between a first state of a switch and a second state of the switch; and
determining a health of the switch based on the transition time;
wherein measuring the transition time includes:
starting a transition timer;
after starting the transition timer, waiting until voltage turn-on transients subside for a blanking time period;
after the blanking time period has concluded, detecting a voltage spike;
stopping the transition timer when the voltage spike is detected; and
reporting a turn-on transition time.
19 . The method of claim 18 , wherein:
measuring the transition time further includes turning on a contactor to provide voltage to a coil of the switch to move an armature of the switch from a first position to a second position;
the transition timer is started when the contactor is turned on; and
the voltage spike is detected when the armature stops after the blanking time period has concluded.
20 . The method of claim 19 , wherein measuring the transition time further includes:
turning off the contactor to cut off the voltage to the coil of the switch to move the armature of the switch from the second position to the first position;
incrementing a cycle count when the contactor is turned off;
starting the transition timer when the contactor is turned off;
waiting until voltage turn-off transients subside for a second blanking time period;
detecting a second voltage spike when the armature stops after the second blanking time period has concluded;
stopping the transition timer when the second voltage spike is detected after the second blanking time period has concluded; and
reporting a turn-off transition time.