Inductive load: Vacuum Pump motor 115VAC 0.9Watts
Resistive load: Heater 115VAC 0.75 Watts
What is the best way to control these from a PLC output? SSR or a mechanical relay? Control as in turning ON/OFF 115VAC to Pump and heater. Neither will be toggled ON/OFF rapidly. At least 30 or more minutes in between an “ON to OFF to ON” again cycle. Reliability of the relay over cost is of utmost importance. Willing to use a relay rated for 2 or three times required current rating for the sake of reliability in the long run over cost. Vacuum pump being on is not a concern. Heater not getting turned off is. There is a secondary temperature monitoring scheme that will e-stop the system and cut-off power. Want to avoid this if at all possible. This will be a 24/7 in use system. Heard of mechanical relay’s getting fused in ON position and SSR’s failing in ON position. Which one is the lesser of two evils for inductive and resistive loads? As in what is the best and safest option? SSR (provided correct type is used for inductive and resistive loads) or, a Mechanical relay?
Thoughts? Suggestions?
Thanks.
Resistive load: Heater 115VAC 0.75 Watts
What is the best way to control these from a PLC output? SSR or a mechanical relay? Control as in turning ON/OFF 115VAC to Pump and heater. Neither will be toggled ON/OFF rapidly. At least 30 or more minutes in between an “ON to OFF to ON” again cycle. Reliability of the relay over cost is of utmost importance. Willing to use a relay rated for 2 or three times required current rating for the sake of reliability in the long run over cost. Vacuum pump being on is not a concern. Heater not getting turned off is. There is a secondary temperature monitoring scheme that will e-stop the system and cut-off power. Want to avoid this if at all possible. This will be a 24/7 in use system. Heard of mechanical relay’s getting fused in ON position and SSR’s failing in ON position. Which one is the lesser of two evils for inductive and resistive loads? As in what is the best and safest option? SSR (provided correct type is used for inductive and resistive loads) or, a Mechanical relay?
Thoughts? Suggestions?
Thanks.