V0N_hydro
Member
Hi
We have 12x Bosch 4WRPEH 100l/min proportional valves. These valves have a 4th spool position that closes the actuator if the proportional valve power supply is turned off.
Due to the hydraulic system design we were forced to de-energize the proportional valve power supplies with the emergency stop button.
When the proportional valve power supplies are switched on or off we are observing spikes in the output of the vibration sensors (5 on each unit). This is a hydroelectric power plant with two units. The vibration sensors on both units report vibration over the trip threshold if the e-stop on either unit is pressed. This occurs even if the unit is at a stand-still and there is no oil pressure in the hydraulic system (so no chance of any actual vibration).
You can imagine the confusion when pressing the e-stop on the unit that is not running results in a trip (due to false vibration) on the other unit.
The only thing the 2 units have in common is the 24V DC power supplies are fed from the same battery bank.
I think some EMF kickback from the proportional valve linear motors or inrush current is causing a voltage fluctuation and the vibration sensors (Hansford HS-420) are overly sensitive to changes in supply voltage.
I put the fluke in min max mode on the supply to the vibration sensors and it changed by 0.2V when the e-stop was pressed.
Has anybody ever had to use a freewheeling diode on a proportional valve power supply? We do this for all the solenoids on the HPU.
Has anybody ever had an instrument that was sensitive to transients in power supply?
thanks for any thoughts.
We have 12x Bosch 4WRPEH 100l/min proportional valves. These valves have a 4th spool position that closes the actuator if the proportional valve power supply is turned off.
Due to the hydraulic system design we were forced to de-energize the proportional valve power supplies with the emergency stop button.
When the proportional valve power supplies are switched on or off we are observing spikes in the output of the vibration sensors (5 on each unit). This is a hydroelectric power plant with two units. The vibration sensors on both units report vibration over the trip threshold if the e-stop on either unit is pressed. This occurs even if the unit is at a stand-still and there is no oil pressure in the hydraulic system (so no chance of any actual vibration).
You can imagine the confusion when pressing the e-stop on the unit that is not running results in a trip (due to false vibration) on the other unit.
The only thing the 2 units have in common is the 24V DC power supplies are fed from the same battery bank.
I think some EMF kickback from the proportional valve linear motors or inrush current is causing a voltage fluctuation and the vibration sensors (Hansford HS-420) are overly sensitive to changes in supply voltage.
I put the fluke in min max mode on the supply to the vibration sensors and it changed by 0.2V when the e-stop was pressed.
Has anybody ever had to use a freewheeling diode on a proportional valve power supply? We do this for all the solenoids on the HPU.
Has anybody ever had an instrument that was sensitive to transients in power supply?
thanks for any thoughts.