Start/Stop Control

Start/stop control is one of the most fundamental compressor operation modes. It is a control approach where the motor driving the compressor is turned on or off in response to the machine’s discharge pressure rather than idling.

The air compressor control method works using a pressure switch. When the system pressure drops to a specific low set point (cut-in), the compressor starts. Once the pressure reaches the predetermined high set point (cut-out), the motor powers down entirely.

The start/stop control mode is essential for maximizing compressor energy savings in facilities with infrequent air demand. Because the machine draws zero power when turned off, it is a highly efficient setup for smaller and tank-mounted reciprocating compressors, such as those engineered by Quincy Compressor.

FAQs

Start/stop control turns the motor off when air isn’t needed and on when the pressure falls below a set point, whereas continuous run or constant-speed keeps the motor running even when no air is being compressed. It means the start/stop system only consumes power when actively compressing air.

Because of its configuration, start/stop mode is ideal for intermittent use, while continuous run is better for high-demand, heavy-duty cycles. In high-demand applications, constant-speed systems are more suitable to prevent excessive mechanical wear caused by continuously turning the motor on and off.

This control method works best when the compressor runs for short periods and stays off for longer intervals. In applications with low and intermittent demand, the motor stops completely when the desired pressure is reached.

Quincy Compressor’s industry-leading reciprocating air compressors are well-suited for this control type. It provides reliable and on-demand power for applications, such as:

Auto body shops
Agricultural operations
Light manufacturing
Dry cleaning facilities
Construction sites

During off-cycles, a continuously running compressor wastes energy while unloaded. The start/stop control prevents idle power consumption and helps maximize energy savings. Since the motor only runs when necessary to replenish the tank, it reduces overall energy consumption and costs in applications with infrequent air demand.

Starting an electric motor requires a surge of power. If the air demand causes the compressor to start and stop too frequently, it can negate the energy savings and overheat the motor. That’s why proper receiver tank sizing is also critical to prevent wasting energy.

Many modern air compressors offer a dual control feature. This system combines start/stop and constant-speed capabilities, making it ideal for light shifts and continuous runs for heavy-production shifts.

The dual-control design allows operators to switch between start/stop control manually. This approach optimizes energy efficiency for different duty cycles, offering maximum flexibility and protection for the equipment.

Instead of turning the compressor motor off when the target pressure is reached, modulation keeps the motor running continuously while restricting air intake. This design allows the easy adjustment of output to match demand.