ith the cost decline of the GU10 spot, it has been gone into ordinary people home and usage increased year by year. The attendant problem is that many GU10 spots defect only in several months. Thus customers argue that LED lamps are not long lifespan as promised. To help clients avoid misunderstanding, BWLED R & D department will analyze the root causes of failure lamps. Excluding the manual defect and improper usage, here we only analyze the product quality problems.
GU10 lamp is mainly composed of three parts: power, light source and heat sink. Power and light source is the core. So the defective lamp may be caused by one of these two parts. Although the heat sink cannot directly lead to failure, there are still some problems caused by heat sink quality.
1. Driver’s problem
(1). IC failure
Used some small companies’ driver solution or immature solution
b. the IC was operated with overload which cause the explosion
(2). MOS pipe failure
used the refurbished FET (Field Effect Transistor) or small companies FET. Overload operating causes overheating or explosion.
(3). Capacitor failure
The company used some unknown capacitors which standard temperature is 85 ℃ or life time is only 500-2000 hours. These conditions are easy to lead to capacitor failure.
(4). Transformer failure
Used aluminum-clad wire line, leading to overheating of the fuse. The overload operating of transformer will overheat, causing damage;
(5). Bridge Rectifiers failure
Used small chips and the lamp has been operating for long time, which causing overheating and explosion;
(6). diode failure
The output current exceeds the selected diode’s operating range, causing the entire driver cannot work.
The lamp stability is due to the power solution; The durability depends on MOS and capacitors.
2. Light source problem
(1). Gold thread break
used very thin gold thread, or used copper or alloy thread. The glue cracked and pull off the thread;
(2). Chip failure
a. The chip was vulcanized for insufficient sealing glue.
b. Large current leakage caused by the poor quality of the chip.
c. Current power supply output voltage does not match the chip, leading to burning.
d. Unqualified glue and fluorescent powder used, which cause cracking, chip thread break and color temperature drift obviously.
3. GU10 spot heat sink problem
Heat is the enemy of GU10 spot bulbs. High temperature will damage the power and the light source. So the heat sink indirectly affect the GU10 lamps’ life time. The high temperature is usually caused by three aspects.
(1). the heat sink dimension is insufficient. Such as a 4W heat sink is used for a 6W GU10 spot.
(2). used the bad material, such as die casting aluminum, icon, plastic coated aluminum, and plastic. The following diagram shows different body materials have different thermal conductivity.
(3). heat sink design problem
A bad heat sink design will cause the heat cannot spread evenly to every part of the body. Thus the heat around the chip and driver is very high.
