Merry Christmas and Happy New Year to our loyal readers. We hope you have a wonderful 2015.

We get this question all the time! How much does a certified truck scale cost? New or used? Well, in today’s entry we are going to give you a rough idea of how much a truck scale costs. Now in our example we will be looking at new truck scales.

As for used scales, generally if you’re looking for things like a used 70 footer watch out for things like too much rust and excessive wear on the under side of the deck. And let’s face it when you’re talking about a truck scale, it’s an item that is going to be outdoors in the elements and if it has decent traffic counts, it could go through a lot of wear and tear and in most cases a used truck scale will have little or no warranty. Just some things to consider when you’re looking at a used scale.

Now, let’s take a look at a new truck scale. Generally, in 2021 you can expect to pay Continue reading →

The Third installment of the series “The Power of Zap” is called Grounding 101. Jim Daggon, Rice Lake senior product engineer and Chuck Crowley senior technical support manager focus on the importance of proper grounding for safety and the performance of sensitive electronic devices. The idea of grounding is that the earth itself acts as the electrical ground, providing not only a common reference for all electrical devices, but also a standard between devices regardless of location. The earth is used as the common reference conductor.

The consideration that the earth acts as a constant conductor is the underlying principle, and in the larger sense, it does. However, the connection to the ground or “earthing” needs to have the lowest resistance possible. Any resistance due to improper or faulty connections will allow the presence of a current to flow. In the context of safety, current flowing through a vital organ is what causes injury or death. The frequency of the alternating current, the duration of contact, and the path of contact are all important factors in determining the severity of the shock. The connection to the earth consists of two basic parts: the grounding electrode and the connection (or bonding) to that electrode. Any resistance introduced in the grounding path could lead to a damaging or dangerous condition.

The relationship between resistance, current, and voltage is revealed in Ohm’s Law1:
I = V / R
Where :
I = current flow
V = voltage
R = resistance2

Using this equation, if the resistance is 0, then the current flow will be maximized in the ground circuit. (This is what you want, not current flow in another path that does not include the ground, but may include YOU!) The accepted National Electrical Code (NEC), standard for a grounding circuit is 25 ohms or less, but much lower values can be obtained using multiple grounding electrodes. Click here to read the entire part 3 article.

Thank you to the Men and Women who have served our country. We don’t say it enough, but we truly appreciate you and your efforts.

In our last article we looked at a few of the possible sources of electronic equipment damage due to power transients. In this article Jim and Chuck will further investigate ways to troubleshoot and correct these transient conditions to protect electronic equipment.

Although there are four types of power anomalies, there are three ways that transient voltages can enter an electronic system (including scales):
•The power source
•Peripheral ports
•Electrostatic Discharge (ESD)

The basic goal of any protection device is to divert the excess charge along a path to ground that does not include any of the sensitive electronic components that will suffer damage. This is done in a number of ways and the methods are tailored to the source of the excess voltage.

The power source

Most electronic scales need a source of AC power. Some battery-operated units can be exempt from this type of disruption, but during their charging cycle, they become susceptible, sometimes even if the unit is turned off. Most electronic devices use a power supply that converts the raw AC power into a lower DC voltage. A linear power supply can shield against passing many transients through to the circuitry, but more modern switching power supplies can block many common transients also. The power source can contain any combination of surge (overvoltage for one half cycle or longer), sag (under voltage for one half cycle or longer), or transient, over or under voltage that is very short in duration (less than one half cycle), but can contain very high voltage peaks.

Most modern electronic devices are internally grounded and protected from a static electricity discharge from any outside surface of the device. The problem becomes greatly magnified when either the grounding is subverted or the case is opened. The use of a three-to-two wire adapter on the AC cord is one of the most common ways this is accomplished. The ground pin on an AC cord and receptacle is provided to do just that—connect the device to a legitimate ground (see sidebar “Respect for the AC receptacle”).

If an extension cord is used, be sure that not only is the grounding pin intact on both ends, but that they are connected. Use an ohmmeter to confirm this before plugging in either end of the extension cord. A simple method to check the basic wiring and to ensure that the ground, neutral and hot wires are connected properly is to use a simple tester as shown below. These are available in hardware and electrical supply houses and are quite inexpensive. Any problems that show up using this test require immediate action. NO EQUIPMENT OF ANY SORT should be plugged into any receptacle showing a wiring problem. Remember this device will only tell you if the wires are connected properly, not if the quality of the connection is good or even adequate. Once the wiring has been tested for correctness, the problems of surges, sags and transients need to be addressed. These will require more rigorous testing. All three can be monitored using a device which plugs into the receptacle and monitors and collects information such as the voltage, frequency and any transients outside of specified norms. The data is stored and can be downloaded later into a computer for analysis. Click here to read the rest of part two.