Panels 101: Designing and Building Control Panels

The most critical element that shapes a panel design project must be addressed at the very beginning of a project: where is the completed unit going to be installed? This very basic question dictates the type of protection the enclosure must provide to the equipment. The switchgear inside the enclosure must be protected from the […]

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Tech Talk: I need an explosion-proof control panel with a few pilot lights and…

Q: I’ve been buying explosion-proof enclosures and devices from Kele, and I must say that the Hazardous Locations section of your catalog is a gold mine of hard-to-find products! Now I need an explosion-proof control panel with a few pilot lights and externally operable selector switches mounted on the door of the panel. Can Kele help me with […]

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Tech Talk: Timing relays are confusing to me. Can you explain the difference between single-shot and interval timers? What happens if the output driving the relay changes state during a timing sequence?

When all of the possible combinations of timing states and initiating device transitions are considered, a stronger word than “confusing” may be in order! Below are some timing diagrams and sequences of operation in simple terms that may be of help. Since it is an electronic circuit that is energized rather than a coil, the […]

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Relay Fundamentals

Open an HVAC control panel, and you’re likely to find at least one relay mounted inside. Sometimes you find lots of relays! Even though relay technology has been around since the 1800s, there is still a need for relays in control panels. What components make up a relay? How are relays typically shown in wiring […]

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Using a Multimeter Series – Resistance Measuring Basics

“Resistance is futile, Buwhahaha” exclaimed the villain, rubbing his hands together in glee as our hero struggled to free himself from the ropes that bound him. Yep, we’ve all seen those Grade B movies.  Maybe in that situation resistance is futile, but in the world of electronics and HVAC controls resistance (electrical resistance) is very […]

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Using a Multimeter Series – Voltmeter Basics

If you live in the world of HVAC design/installation, sooner or later you’re going to need to take measurements on a circuit using a voltmeter (even if it’s “not your job,” we all know how that goes). So we thought it would be a good idea to put together some basic instructions on using a […]

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“Currently” Playing: Connecting A 4-20 mA Constant-Current Signal To Multiple Loads

One of the most popular and long-lived methods for transmitting analog control signals in the HVAC and industrial control worlds is the “constant-current signal loop.” In this scheme, the value of the current flowing in the circuit is the control variable, rather than any voltages that may appear at different points in the circuit. The […]

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Networking 101: BAS Network Cabling

The various devices comprising a building automation network are either connected by cables or talk wirelessly to each other, or possibly a combination of both.  In Networking 101, we are going to concentrate on network devices connected by cables.  Let’s take a look at the different types of network cables typically encountered in building automation […]

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