МЭЛЗ ДРЛ 500 M (MELZ DRL 500 M)

[Olav]

Hi, everyone,

today I would like to introduce a special mv lamp.
This type was produced by the MELZ company in Moscow from 1956 to 1971.
The special thing about this type of lamp is the lack of ignition electrodes.
I don't yet know why mv lamps were built without ignition electrodes.

Ignition must be carried out with an ignition device via the main electrodes.

This post contains photos of the lamp, a data sheet and an excerpt from a Russian book Применение газоразрядных источников света (Application of gas-discharge light sources).

The lamp in the photo was manufactured in September 1970.



















You can practically only compare the lamps with 400W and 1000W directly. It can be seen that the luminous flux of the TYPE DRL M is lower.
I would be very interested in the reasons why these lamps were produced in the first place. I have a guess, but it has not been proven.
Perhaps normal mv lamps ignite very poorly in extreme cold, and that's why this design?



Regards

Olav

[Ash]

I guess it might have to do with restrike time. Especially as most lighting in the USSR was powered from fairly unreliable grids, sometimes with ineffective short circuit protection too (which means significant dips in line voltage for all connected loads, as result of shorts in unrelated subcircuits)

If there is any interest in full translation of the entire text, ask (I read Russian)

[FrontSideBus]

Very interesting!

[Olav]

Hello Ash,

thank you for your offer.
A translation would be of great help for understanding.

Regards

Olav

[Ash]

Instructions
For the use of high pressure mercury lamps with corrected color type DRL(M)

Technical standard no. SU0.337.052 Technical standard edition 2



I. Purpose of lamps
Phosphored mercury arc lamps of type DRL are intended for illumination of streets, highway roads, insdustrial plants and other objects, not requiring high quality of color rendering



II. Main parameters of lamps

Lamps of type DRL are made in the following four powers :
DRL250 - 250 Watt
DRL500 - 500 Watt
DRL750 - 750 Watt
DRL1000 - 1000 Watt

The mentioned lamp types are are intended for connection into AC mains of frequency 50Hz and nominal voltage 220V. Connection of lamps to the mains is done with a specialised connection devices, satisfying the following technical standards :
For lamp DRL 250 - device 0.25/0.22
For lamp DRL 500 - device 0.5/0.22
For lamp DRL 750 - device 0.75/0.22
For lamp DRL 1000 - device 1.0/0.22

In the first 7 minutes after switch on the lamp in normal thermal conditions (15..25C) its electrical and luminous parameters shift (unstable mode), then become constant (stable mode) given stable line voltage. At low temperature of ambient air the process of stabilization of mode gets longer

Electrical and luminous parameters of the lamps are stated in the following table :

Marking of lamp type | Nominal power W | Working current A | Starting current A | Voltage of lamp V | Nominal initial light flux Lm

DRL250 | 250 | 2 | 5.5 | 120-150 | 9500
DRL500 | 500 | 4 | 12 | 120-150 | 21000
DRL750 | 750 | 6 | 15 | 120-150 | 33000
DRL1000 | 1000 | 8 | 18 | 120-150 | 46000

The initial light output of the phosphor, applied on the internal surface of the lamp envelope, in the red area of the spectrum (in the range of wavelengths of 610..770nm), improving the color parameters of the mercury discharge, make up into 6% of the overall output of the lamp



III. Connection of lamps to AC mains

The principal schematic of connection of lamps to AC mains is stated in fig. 1

1. DRL lamp
2. Connection device
3. Resonant capacitor for 250V working voltage for correction of power factor of installation
4. Fuses for current rating 20A for lamps DRL250 and DRL500 and 30A for lamps DRL750 and DRL1000
C1, C2 - Capacitors for protection of the mains from RF interference of capacitance 0.5uF

The capacitance of capacitors for power factor correction is stated in the following table :

Type of lamp | Recommended capacity in uF
DRL250 | 20
DRL500 | 40
DRL750 | 60
DRL1000 | 80



IV. Conditions of use

Normal burning position of the lamp, to which apply the warranties for the lamp service life - is vertical cap up



V. RF interference

When lamps are used in luminaires containing embedded connection devices, satisfying specialised technical standards, there is no interference

In all other use cases during lamp starting there may appear RF interference, exceeding allowed norms.

For limiting of the RF interference it is required to : Provide secure electrical connection in all connectors, throughly shield the cables connecting the device with the lamp, ground the chassis of the device and luminaire, install mains filtering consisting of 2 capacitors of 0.5uF connected in series with grounded center point

The mentioned actions must be carried out during the installation of lamps and devices by the customer or installation company, who are directly responsible towards the radio inspection of the state for non compliance to recommended actions

Order 2276





[...] of high pressure (5..10 kgf/cm2). The tube is enclosed in an outer glass envelope of temperature resistant glass (the temperature of the envelope reaches 300..400C), which is internally coated with a layer of phosphor. The lamp is equipped with a screw cap

The structure and way of operation of DRL lamps differs from tubular fluorescent lamps of low pressure. The making of the DRL lamp became possible following success in the development of mercury quartz lamps of high pressure and especially following achievment of new temperature resistant phosphors, using which it became possibe to improve the color rendering of the mercury discharge

Thing is, the color rendering of discharge in mercury vapor, giving intensive light of blueish color, makes it impossible to correctly render color shades : Faces of people become dead pale, lips - blueish grey, familiar colors of surrounding objects are warped. For this reason mercur lamps without phosphor are considered practically non useful for lighting even in those cases, when there are no high demands to the color rendering, for example in street lighting

The main disadvantage of mercury discharge application in lighting is the lack of orange-red radiation in its spectrum. This disadvantage had been significantly overcome using a phosphor, which is applied to the internal surface of the outer envelope of the DRL lamp. This envelope is filled with CO2 for the maintenance of the properties of the phosphor and has a shape, which provides during the operation of the lamp uniform temperature of the entire surface, covered with the phosphor ("isothermal" shape). The phosphor is chosen so, that it will sink well the invisible longwave UV radiation, that comes through the quartz walls of the mercury burner, and convert it into orange-red visible radiation, which makes up approximately 7% of the entire light flux, this way correcting the color rendering of the output of the lamp. At the same time the phosphor virtually doesn't sink the visible intensive radiation

If we remember, that in tubular fluorescent lamps of low pressure the light output of visible radiation of mercury discharge is very low (barely reaching 5 Lm/W), while in incandescent lamps of medium power the light output of visible radiation makes 15 Lm/W, and the high light output of fluorescent lamps is achieved mainly by the lighting of phosphors, then the difference in the way of operation of those lamps and DRL lamps becomes clear

Table 7
Technical characteristics of lamps DRL

Lamp type | Power W | Lamp voltage V | Current A | Light flux Lm | Size mm : Diameter | Full length | Service life Hr

Four electrode lamps according to state standard 16354-70
DRL80 | 80 | 115 | 0.8 | 3200 | 73 | 167 | 7500
DRL125 | 125 | 125 | 1.15 | 5600 | 77 | 187 | 7500
DRL250 | 250 | 130 | 2.15 | 11000 | 91 | 227 | 7500
DRL400 | 400 | 135 | 3.25 | 19000 | 122 | 292 | 7500
DRL700 | 700 | 140 | 5.45 | 35000 | 152 | 368 | 7500
DRL1000 | 1000 | 145 | 8.0 | 50000 | 181 | 410 | 7500

Two electrode
DRL250M | 250 | 140 | 10500 | 125 | 320 | 5000
DRL500M | 500 | 140 | 21000 | 145 | 360 | 5000
DRL750M | 750 | 140 | 33000 | 170 | 390 | 5000
DRL1000M | 1000 | 140 | 46000 | 200 | 440 | 5000

Notes :
1. Cap of lamps DRL of 80 and 125W - type E27, others - E40
2. Starting regulation devices for DRL lamps are made for connection into 220V mains


The light flux and starting of DRL lamps is virtually independent of the temperature of ambient air, which puts them at advantage vs fluorescent lamps. To the advantages of DRL lamps shall be attributed their comparatively small size, and lower use of copper and silicon steel in the starting regulation device (0.42 grams copper and steel per 1 Lm light flux, while for fluorescent lamp LB-80 it is 0.86 grams respectively). The main sizes, luminous and electrical parameters of DRL lamps are provided in table 7

2-985
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[Olav]

Hello Ash,

thank you very much for your translation. That was a lot of work and a lot of time for you. The texts from the book are now plausible. I have now found the technical reasons for the design of these lamps. Our guesses were not in the right direction. The information is from a Russian website. I think about, if the very detailed text in Cyrillic is useful here or not.

In the summary, the statement is as follows:

1956 began the production of the first high pressure mercury vapor lamps in Moscow. In the first few years, it was not technically possible to seal the molybdenum strips of the starting electrodes in the quartz tube in production. For this reason, the simple design was built with only two main electrodes and an external ignition aid. Photos will follow later.

Thank you very much Ash.

Regards

Olav

[Andy]

Thanks for posting this Olav and thanks Ash for the translation.

It is certainly an interesting lamp and unusual wattage.
I rememeber seeing one of these for sale a couple of years ago but it was unfortuantely too expensive.

It is good to finally learn the reason for this design of lamp. I would never have expected this to be the reason!

[Globe Collector]

Hello Everybody, just chiming in to let people know I'm briefly online.

Is it true that photos are "pruned" after 90 days to conserve on memory space on the server?

Just take me a bit to get used to this as building up a library of photographs of our collections is what I perceive as one of the more important functions of these sites.

[Andy]

Hi Andrew,

Glad to see you on LR!
I'm not aware that photos are pruned after 90 days, but someone correct me if I am wrong.

Photos uploaded to the gallery are permanent and I would love to see you adding some of your collection to the gallery here.

[Kev]

I would like to get my hands on some soviet era lamps.