Solenoid Duty Cycles

'Continuously rated' means that the solenoid can be left on without overheating. The force exerted and the power consumed are then the basic continuous rating values to which all other ratings are referred. In the case of an AC solenoid the continuous rating refers to the solenoid in the closed position only. If the solenoid plunger is withdrawn, the 'inrush' current will rise to a high value; and if left energised, will burn out. A continuously rated DC solenoid can be left energised continuously, irrespective of the plunger position.

In many applications a solenoid is energised for only a short period and then left switched off for some time so that it can cool down. Under these circumstances the solenoid coil can be wound for much higher power than the continuous rating value. As a result, higher force can be obtained with the proviso that the solenoid is not continually energised. This versatility in the amount of winding wire needed to produce a solenoid allows BLP to produce a range of low cost solenoids to meet the cost sensitivity of most applications

In some cases, solenoids may be required for intermittent operation, but not on a fixed time cycle. For guidance on this, the maximum 'on time' for the different ratings on a single cycle basis is given. This is the maximum time this particular solenoid can be left energised when starting from an ambient temperature of 20ºC.
When AC solenoids are used on fast cycling, 'inrush current' occurs at each closure. With fairly long cycle times where the solenoid closes and then remains energised for some time, the increase in power during the operate period has no significant effect. If the cycle time is fast, so that the solenoid barely has time to close before it is
de-energised again , then the inrush current causes considerable extra heating effects. Fast cycling AC solenoids may require the use of continuously rated solenoids for intermittent duties.

Applications for BLP Solenoids

Direct Acting

BLP's standard solenoid range meets the widest possible range of applications. Solenoids are available in a variety of sizes and types - AD / DC, Miniature,small, Heavy Duty, High Force / Size Ratio, Combined Pull and Thrust, Low noise and Tubular solenoids.

Small Solenoids ( Low cost Solenoids )

Our solenoids can be found in the most diverse applications - Photocopiers, Vending Machines, Residual Current Devices, Locking Mechanisms, Coin Mechanisms, Switching Mechanisms, Valve Actuators and many more. We have found that over the years the requirement for small solenoids has increased as electrical products become smaller. BLP can manufacture solenoids that are small enough to be mounted on a PCB board.