Does your installation require low voltage (12 or 24vdc) and you still want the reliability that rotary paddle level indicators provide? You don’t have to settle for a lesser rotary product… check out a practical solution that Monitor offers in their rotary paddle level indicator line.
Most manufacturers of rotary paddle indicators do not offer a highly-reliable 12 or 24vdc option. Monitor does. Monitor Technologies implemented a design change in the 12 and 24vdc rotary paddle bin monitors. The change dramatically improved the performance of these models and made them a viable solution for process oriented systems requiring a low voltage power source, minimal installation cost, and frequent level cycling.
Rotary paddle bin level monitors use a small motor to rotate a paddle that protrudes inside a silo or bin. As material surrounds the paddle, its rotation is halted. Within the bin monitor, the motor continues to rotate creating an internal cam action which actuates the output switch. In addition, the motor is shut off through the actuation of a second switch within the bin monitor.
Typically when specifying a rotary paddle bin level switch, the operating source of the sensor (115vac, 230vac, 24vdc, etc.) matches the operating requirements of the internal motor. This results in AC powered bin monitors using AC motors, and DC powered bin monitors using DC motors.
Economical DC motors are not designed to run continuously, and therefore their use in rotary paddle indicators result in compromised longevity. These motors use internal brushes and commutators which physically wear as the motor rotates. Life expectancy is only 5,000 hours (e.g. six months of continuous operation) depending on application load and temperature. (Figure 1 shows a DC motor).
Economical AC motors can be sourced that have a long operational life. The permanent magnet synchronous AC motor uses technology that has no physical wear characteristics. Applications have operated successfully using this motor within the Monitor Model KA rotary paddle bin monitor for over 20 years. (Figure 2 shows an AC motor).
The internal construction of Monitor’s 12/24vdc powered KA and KAX bin monitors is different. Instead of compromising the design with a lower-life DC motor, the Monitor rotary paddle bin monitor includes electronics that converts the 12/24vdc power source to 6vac energy that is used to operate a 6v AC motor. The Monitor 12/24vdc powered rotary paddle bin monitor is designed to save cost without the sacrifice of product performance and life expectancy.
So if you’ve been inconvenienced by poor performing low voltage rotary paddle indicators, or you’ve been told that all low voltage systems will work equally well, buyer beware! Look into Monitor’s practical 12/24vdc solution and rest well.
Visit www.monitortech.com or contact one of our Application Engineers at fred@monitortech.com.
Figure 1
Figure 2
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