Oct 14, 2011
Lumen Depreciation and Lamp Mortality Analysis
Two of the most notable benefits to the Tri-R solution are the decreased lumen depreciation and the extended lamp life. This document is provided to better explain these benefits through a technical explanation of how they are calculated and proven.
Most common High-intensity discharge lamp (HID) ballasts are referred to as ‘magnetic’, being an iron-core transformer that operates at 60Hz, power line frequency, and drive the bulb at the same frequency. Magnetic ballasts use a capacitor and/or igniter, are generally heavy, run hot by design, are sometimes noisy, making an audible ‘hum’ when in use and tend to lose their electromagnetic strength over time. The latter is known, typically, as degradation and is an unavoidable result in the magnetic field the ballast uses to operate the lamp.
Other electronic ballasts offer some improvements over magnetic, but still operate at relatively low drive frequencies (between 60Hz, power line frequency, and 50kHz). They are able to offer a “softstrike” and “dormant-mode” through the use of a microprocessor. The microprocessor generates extreme heat (similar to a computer, which requires a cooling fan) and therefore these other electronic ballasts attempt dissipating this additional heat through “fins” on the exterior of the ballast. Even with the “fins” design, major failures due to overheating have occurred with other electronic ballasts, which have jeopardized their success in the industry. Additionally, they typically come with upper temperature limits which exclude them from most exterior applications as well as those utilizing a sealed fixture design such as hazardous locations and other adverse conditions
Tri-RHID is an electronic ballast operating at over 100,000Hz bulb drive frequency. Tri-RHID is able to offer all of its benefits through Tri-R Systems‟ patented NON-microprocessor design. Due to the absence of a microprocessor, Tri-RHID is able to operate at a much lower temperature creating a reliable environment for the electronic components. Additionally, all Tri-RHID ballasts are completely sealed with an epoxy potting material and together the entire design system has gained UL® certification for “inside” or “outside” the fixture.
Tri-RHID Technology Overview
Lamp Re-strike Sequence
The Tri-RHID ballast design provides a control system strike sequence that is significantly slower
and less often than other ballasts on the market. It takes into consideration any existing lamp
conditions such as being hot or being dormant for some time. An initial cold lamp strike will
generally occur approximately 30 seconds after power is applied, and a hot lamp re-strike is much
quicker than other magnetic and electronic ballast technologies. So, the lamp is struck less, thus
reducing wear on striking electrodes.
Strike/Run Mode Sensing
The Tri-RHID ballast uses a soft-strike sequence and through its ‘run condition sensor’ that
disables the striking process and prevents unnecessary lamp striking. As the lamp begins its
warm-up and run, sensors within the ballast determine the lamp‟s state as being within acceptable
limits. In the case of a shorted lamp (or sometimes referred to as a false-run) the run mode is
terminated and is restarted from a “re-strike condition” sequence.
Strike, Lamp Warm-up Process
The Tri-RHID ballast begins the strike sequence with, a ‘gas excitation sequence‟ being applied to
the lamp for approximately 1.5 Seconds. Being of less voltage than a strike, it actually enhances
the lamp condition for striking by causing motion in the gases. This is by inducing a small
electromagnetic field between the striking electrodes which helps the lamp gases to blend. These
gases often segregate when cooled and this separation often cause the need for additional strikes
between the electrodes to effectively strike the lamp, thus reducing electrode life when using other
Strike Voltage Incline Process
The Tri-RHID ballast follows the ‘gas excitation sequence’ with it‟s patented lamp strike
sequence‟ for a period of 0.5 seconds. During this time, the voltage is slowly increased, so that
when the lamp accepts the strike voltage (creating a successful arc), it is at a ‘minimum’ acceptable
level for the lamp and not in excess. In the case of a hot lamp, the voltage ramp is terminated at
the ANSI maximum level so that excessive electrode wear is eliminated. When an effective strike
occurs in the lamp, the ballast drive power is restricted to prevent the unnecessary lamp abuse
caused over-power while in a run condition.
Lamp Lumen Depreciation and Early Life Failure
A primary factor affecting the decline in the lumen output of a lamp over time is the harsh
environment that a magnetic ballast creates through the effect of its electromagnetic transformer.
Magnetic ballasts will strike a lamp at every 60Hz voltage peak, which means there are 7200 strikes
per minute until the lamp ignites. The Tri-RHID ballast soft strike only strikes a lamp a maximum
of 2 times per minute. The strike sequences have been captured in Figure 1.1 below.
The ineffective and unnecessary re-striking of magnetic ballasts (as shown above in Figure 1.1) greatly deteriorates the electrodes. Evidence of this additional abuse is shown in Figure 1.2 below. Each of these electrodes has driven lamps for 4,000 hours in a 12 hours on and 12 hours off sequence to emulate typical dusk until dawn operation.
Through the diagnostics available within the Tri-RHID ballast, it is able to determine that the lamp has failed and enters a dormant, "non-striking" state, not using unnecessary energy and not causing any unnecessary harm to the ballast or components. This helps to extend the life the Tri-RHID ballast significantly.