Education Category - Page 4 of 14

The Most Important Factor When Choosing a Motor Drive

Close up of a Reliance Electric GV3000 Motor Drive — A motor drive can run on DC power, or use AC power like the 15V4150 GV3000 Drive from Reliance.

There are several things to consider when sourcing a drive to use with a motor. These include

Function. What will the components be doing? Make sure to choose drives and motors designed for the same purpose.
Location. Industrial components are specifically designed to hold up to the more rigorous demands of the factory floor. Some products may be rated for outdoor use while others might be restricted to inside locations only.
Compatibility. Unless you need a conversation-starting paperweight, an incompatible drive is worthless.
Cost. What’s your budget? Hint: this is where reconditioned and surplus products really shine. They’re often a fraction of the cost of new.

While all of these factors are important and should be a part of your decision-making process, none of them make the top of the list.

So what does?

Current and Voltage.

Always be sure as you look at drives that their output voltage meets the input voltage rating of your motor.

Also, be sure the drive’s output current rating meets or exceeds the FLA (full load amperes) rating of the motor. You can typically find the FLA on the motor’s nameplate data.

If you have more questions about sourcing the correct motor–or any other product–for your needs, contact our team today.

Why do PLC Manufacturers Provide Derating Curves?

PLC power supply, 57c493. Power supplies like this usually include derating curves in their manuals. — Reliance Electric 57c493 Power Supply for the Automax PLC

If you’ve done any work around a PLC (programmable logic controller) or DCS (distributed control system), you’ve probably had an opportunity to see mention of derating curves. These are often included for the power supply. But why provide these little charts? What are they good for?

Derating curve example. Derating curves are used for equipment like PLC power supplies. — Source: Wikimedia Commons

Heat dissipation curves are usually part of the product manual. They can help the end-user determine the de-rated power value at the expected operating temperature. In manufacturing settings where power supplies may be enclosed, temperatures can quickly become elevated.

But increased heat can reduce output due to a loss of thermal dissipation. Frequently, this loss is due to the breakdown of conductive fillers that provide the electrical connection between a substrate and mounted components. Accordingly, if the temperature becomes too high, the conductive particles that provide electrical connections become entrapped in cured adhesive and can no longer function as they should.

PLC Derating charts offer insight into just how much heat will affect output. This offers the end-user the opportunity to consider upsizing their power supply to compensate, or to provide external cooling to reduce the amount of heat. This is often the best course of action since heat will damage and often limit the lifespan of components. With this in mind, heat control should always be part of your plan.

Need a power supply for your Reliance AutoMax system? We have many in stock, including several revisions of the Reliance 57c493 Power Supply.

Ladder Logic: Here are the Basics

What is Ladder Logic? A Definition

Ladder logic stems from the history of relays. At one time, relays were the primary control for most automatic systems. These electromechanical devices consisted of coils and contacts that they moved. Energized coils moved their contacts from their resting position to their active position (either closed to open or open to closed.)

Close up image of a real ladder and a light bulb. Visual representation of the inspiration basic ladder logic programming can allow for. — Ladder logic is shaped like an actual ladder, and is read from top to bottom/left to right.

In practical application, a ladder diagram showed how to wire relays together. This diagram looked like a drawing of a standard household ladder with uprights and rungs. Modern-day ladder logic still follows these conventions. Relays did (and still do) their job well, but can be cumbersome due to the sheer size of multiple relays wired together. This is where programmable logic controllers using ladder logic can be advantageous: able to do the same kind of job but in significantly less space.