Issue 152 November - December 2022

Please note: The issue content below is just a summary of the articles in the printed magazine.
The articles are not available on-line. Please refer to the printed magazine for the complete article.
VFDs in stock and ready to go

f you are having to wait for a variable frequency drive but need it straight away, Advanced Motor Control (AMC) can solve your problem right now and dispatch a drive to you today.

Managing director, Mark Empson, says AMC has abundant stocks of drives in Christchurch to cater for up to a year of demand since the company committed to advanced ordering three years ago.

He says based on what the company has been selling for the last 20 years, AMC offers immediate availability of their full range drawn from four international suppliers.

“We have permanently on hand at least nine months of stock based on current and projected sales and all the engineering expertise you need to ensure you get the right solution.

“The drive we supply might not be the brand you are used to, but it will be fit for the purpose you want and will get you back in production immediately.”

Empson says as a value-added motor control and automation equipment supplier, AMC is committed to stocking ahead to help not just regular customers but also anyone caught out by a breakdown.

Making EESS alternatives to SDoCs safer

Changes to improve the certainty that declared medium and high risk articles are safe to be installed or used get underway on January 1, 2023. Importers and manufacturers will have to ensure their products have been properly tested and certified for sale in New Zealand and also marked with the right voltages.

While the new rules apply to new imports, the old rules remain in place in parallel as products in stock or ordered before the end of this year pass through the system. Principal technical advisor for WorkSafe Energy Safety, Peter Morfee, says when the transition to the new regime is completed, WorkSafe will issue a Gazette notice that will turn off the old rules and fully implement the new and more stringent regime.

This gives users and installers plenty of time to learn about how fittings and appliances covered by the risk categories have to be marked to show compliance and how their use in New Zealand is made lawful by the enhanced recognition of the EESS system adopted in most Australian states and the formal recognition of the NSW product approval system.

The changes have been made because almost every electrical product approval for supply in New Zealand originates in Australia and the way the harmonised system has been applied over recent years has not worked as hoped in New Zealand.

How to improve electrical compliance and safety

Electrical inspector Miquel van der Wees suggests compliance changes without bringing back the utility inspectorate

The 1992 changes to the Electricity Act did away with the network inspectors and made prescribed electrical work self-certifiable, apart from the high-risk work. Electricians no longer have an inspector looking over their shoulder to ensure general prescribed electrical work is done to a standard. Economic pressure, lack of accountability and a lack of training have resulted in a ‘race to the bottom’ where the cheapest quote will generally get accepted and the job is often completed by unsupervised apprentices or badly trained electricians.

This has led to an epidemic of non-compliant and unsafe work being performed on electrical installations. Ask any electrician and inspector and they will happily show you pictures of bad workmanship they have found and corrected. Complaints to the EWRB are scarce, mainly because people don’t want to get involved or (in smaller towns) have it known to the other party that they have complained about them.

When the electrical inspector inspects the ‘high-risk’ prescribed electrical work, the inspector will, (in most cases) contract to an electrician. This results in a working relationship but also creates a dependence, where the electrician has the financial ‘power’ in the relationship.

Improving equipment efficiency with OEE

It’s now a given that businesses that produce goods need to continuously improve because it doesn’t take too long before a competitor comes out with a superior offering.

However, trying to improve our production processes is easier said than done. Before we can start making changes, we need to know which aspects within our processes need to be improved. In other words, we need to understand our systems better, so that we know which areas to focus on.

Deciding on an area to concentrate on is difficult without hard data. As has been said: “That which can be measured can be managed”. But it’s the measurement and extraction of concrete numeric data from a working process that often presents the first challenge to an improvement routine.

This is where OEE has been able to help many users analyse their processes, which has in turn helped them pinpoint areas that needed improvement. Moreover, OEE data is comparatively easy to generate, and while some have resorted to commercial products, others have successfully accumulated the data for themselves.

Many users of OEE have been surprised by the results and have been able to glean previously unknown information about their processes. This data then proved invaluable for enhancing their systems.

Getting started on a path to digitalisation

Many industrial companies already understand that their operations need to be improved in order to remain competitive and relevant in their marketplace. They know they need to become more efficient but aren’t sure how to do it.

Recent developments have highlighted how dependent companies are on a stable workforce. First there was the Covid pandemic, where many workers were forced to isolate at home and, more recently, the acute lack of available skilled workers has made things more difficult.

These factors have driven home the importance of automation and not being overly reliant on a manual workforce. Further incentives for automation and safer process control have come from the growing fines and reparations being awarded in health and safety prosecutions.

While site engineers, system integrators and electrical contractors can help with engineered solutions, the company-wide process of improving the production process has wider issues to manage in its implementation.

LED drivers and how power is delivered to LED chips

LED luminaires operate with constant current at the individual LED chip level. How that constant current is delivered to those individual diodes is particular to each luminaire’s requirements.

Some products like LED panels, the final supply will be delivered via a constant current driver but need a combination of internal series and parallel circuits to deliver that to a high number of individual chips. Small outdoor lights may require a constant voltage delivery system in parallel to allow for adaptability of the quantity of fittings on one run. Low output stair lights may have a straight series configuration delivered directly from a constant current driver, and large powerful floodlights may require constant voltage output, but to be wired internally in a series and parallel configuration.

Each combination delivers the constant current required, but in a manner that best suits the application, which can be driven by factors such as keeping within separated extra low voltage limits (SELV), or delivering supply to an unknown quantity of chips or managing thermal runaway.

Selecting drivers and cables for LED luminaires

When you have a failed luminaire, the chances are that it will be the driver that has failed rather than the LED chips themselves. There is some good hardware out there for running a quick test to confirm that is the case. There are of course failures of the LEDs and the soldering joints, as well as cases of the LEDs burning out, but the predominance of early failures are within the driver hardware.

As luminaires are ageing, they are becoming obsoleted increasingly rapidly, so finding the original luminaire to replace the faulty one, or even the original driver, is becoming hard or next to impossible in some cases. It would be better just to replace the entire luminaire of course, but finding the replacement that matches in size, intensity and look can be difficult.

The next easiest option is to leave the original light fitting in place and just replace the driver. With the LED chips having extremely long-life spans, the chances are that you can replace the driver and the LEDs will have many hours of life left in them.