Practical Experience

In practice, many of our product support cases can be traced back to product compatibilities and site implementations. To name a few common customer questions: What dimmable drivers can we use? How many lamps can be connected? Can we use brand PPP dimmable lights with your dimmers?

Ideally, to answer these correctly, thorough tests with the actual products shall be in place before installation. Although we’ve been doing these tests with some market available products, the abundance of lighting products in the market and the material costs have forbidden us from doing thorough tests. For example, in a recent residential building project, we worked with an Emergency Battery Kit supplier to validate our LED fixtures that our lights could pass the required discharge duration period to clear the technical compatibility.

That said, we hope that sharing the field encountered issues would let customers understand the pro-and-cons and the technology's limitations. Our goal is to raise to customers to at least test the critical elements for a smooth dimming experience. So, in this section, we shall address issues in the actual installation, such as unstable light at peak level and cross-talk issues when multiple dimmers are in place.

Flickering at Low and Peak Intensities

While our standard LED dimmer modules can support maximum loading of 450W, sometimes, customers only desire to dim a single LED lamp in a room, such as a dimmable LED GU10 lamp. Two things to note in this case, especially when integral drivers are involved, meaning the option to replace the driver is not available.

First, even if our dimmers can support dim-to-off performance (or the lamp no longer provides any visible light output), it's possible to find unstable light output below a specific light output level and just before the lamps go dim-to-off. If we use a power meter to measure the total power consumption of the dimmer and the GU10, we will find the power is already at a low level. To ensure sufficient electricity supply for the entire string, contractors shall set a minimum brightness level with a stable minimal visible light to limit the dimming range.

Second, customers occasionally find that a single dimmable lamp can show flickering at the peak intensity level. In such cases, the integral driver likely causes this by not drawing enough current from our dimmer at the peak intensity level. Hence, the unstable performance of our dimmer at the peak intensity level. This situation is similar to the inconsistent light output with a particular combination of a non-dimmable LED MR16 lamp and a 12Vac electronic transformer. The problem will be solved when more lamps, usually 2 to 3 LED lamps of the same model. Suppose different models or manufacturers’ products are involved. In that case, there must be at least one lamp that can function adequately with the dimmer at the peak intensity to ensure proper operation for the whole string.

Note that our DZ3G4350DIAL and DZ4G450MULT dimmers have different circuit designs, so the issue found with our DZ3G450DIAL may not appear with our DZ4G450MULT at all, vice versa. Electrical Contractors or Lighting Consultants should take note of this possibility and include this in their test for compatibility in their product selection stage. So, if they are aware that the project would require dimming a single light source, they are advised to include this in their tests ahead of time.

Cross-Talk with Multiple Dimmers

Continue with the dimmable LED GU10 lamp examples. After the installation, sometimes Electrical Contractors can find irregular and frequent flickering with most of the lights in the office, which is very annoying. Not only irritating, but end customers usually won’t sign off for project completion in such cases. Suppose the lights are all connected to different dimmers; contractors suspect the dimmers cause that. Furthermore, the situation becomes confusing, especially after the contractor connects a single dimmer with all the same GU10 lamps dismounted from the lighting fixtures, as an isolated circuit (for example, using an AC outlet), everything works fine!

Debugging in this kind of situation can be more difficult if multiple dimmer brands are involved! One way to examine would be to investigate for cross-talk. The cross-talk concern may come into play, especially if the contractor found that changing the light intensity using a dimmer (dimmer A) would also affect other lights’ intensity that is supposed to be dimmed by another dimmer (dimmer B). In other words, the lights in Zone C are also affected by another dimmer in Zone D as we adjust the dimmer for different zones.

Cross-talk refers to the undesired transfer of signals between the communication channels. Cross-talk can be relevant in lighting applications because it is common for all lights to share the Neutral connection for a joint return to the MCB. While this is a common practice, we should understand that this shared Neutral connection approach creates a “common circuit” with many unintended paths among the individual circuits (zones), which results in strange circuit behaviors. Simply put, this makes the circuit paths for multiple dimmers interfere with the others or have multiple dimmers on the same line! To solve this problem, we advise the Electrical Contractors to examine any shared Neutral connection and separate them as much as possible before further investigation.