Fr. David Skelsky, S.J. on the electrical wiring and grounding of the Manila Observatory’s Ionosphere Building

February 11, 2010
To Whom It May Concern:

Inasmuch as the E-mail below contains my name and alludes to what I said and thought, I would like to offer comments if I may.

My interest in the electrical supply of the Iono building centered around the repair of a Rupprecht and Patashnick Dichotomous Air Sampler Model 2025 (RP) owned by the Philippine Government Department of Environment and Natural Resources and stationed on the top of the Iono building since 2005. I shall try to be relevant and focused on the electricity issues at the Iono, but being brief is a difficulty for an experimentalist where detail in not just important but frequently crucial.

1) From information shared with me by Ms Genie (MO contact person for the RP repair) the internal RP computer failed (while on the Iono roof) and the RP was sent to Electrobyte where they replaced the power supply. Whether the power supply was faulty I cannot say inasmuch as the faulty power supply was unavailable. However, we (Ms Genie and I) experienced repeated difficulties with the computer during our later repairs and almost all we traced to poor contacts between the Interface Board of RP and its CPU the 188SBC ? nothing more.

2) In March 2008 the RP (out of specification) came to and was repaired in the lab allotted to me at SEC C room 107A. When we finished our initial repair, although the RP properly needed further replacement of some parts, the RP ran properly and repeatedly (24 hour cycles) in room 107A. It is listed as a 230VAC 50 Hz instrument. However when moved to MO (First venue was the first floor of the solar annex building.) the RP after running for significant periods without a glitch would mysteriously ?hang?. We fashioned a special earth wire to the RP case, but this did not solve the problem.

3) Back in room 107A I subjected the power input of the RP to voltage variations including low, high, and sudden and the responses of the instrument were as described in its Operations Manual. Ms Genie had communicated to me that ?? the power supply ?was destroyed by changing voltages according to the supplier (Electrobyte) in 2007? ? when located on the roof of the Iono as noted earlier. I located no problem, and, programmed properly, the RP, in lab 107A, ran well and repeatedly without any glitch.

4) Now on the roof of the Iono the RP (with a special ground wire to earth) again would mysteriously ?hang?. This ?hang? problem would be traced to poor contacts between the RP computer and its mounting board as noted in 1) above. However, at this time juncture we took a serious look at the electrical phase configuration of the Iono, for we found one of the three phases at essentially ground potential.

a) We went to the electrical transformer room of the main MO building and found that the electrical service was delta and not star as initially expected. With this discovery many former mysteries (transformer ?lows? and Dr. Nofel?s electrical service to the LIDAR) were resolved. The neutral brought in by MIRALCO for star configuration was properly cut, but one of the three phases was essentially at ground potential. This I did not ?understand?, and surfing the Web I could only learn that for the protection of personnel, delta may be earthed with voltages of 600 and above.

b) We traced the main three phase wires to four distribution panels under the stairs at MO with labels of Annex, Radio, Seismo, and Optical and found that neutral cables still existed inside the distribution panels.

c) I orally presented the wiring configuration to Fr. Dan and learned that because of low voltages (190 VAC) the star input was changed to delta. He had no comment about one phase being at ground potential. Fr. Dan did mention, without detail, that lightning has been a problem with the ionosphere wiring.

d) I represented to Ms Genie that our main assignment was to get the RP functioning properly and not attending to an administrative problem of the entire MO, so we returned to the Iono. At the Iono main circuit box we measured each phase to earth: left phase: 220 VAC, middle phase: 220 VAC, and right phase: 4.5 VAC. Clearly the right hand phase was pinned to earth somewhere. Yes, this I did not ?understand?.

5) Further observations in the Iono:

a) The main circuit breaker box mounted in the middle of the west wall is serviced by three heavy wires ? left phase, middle phase, and right phase. A 230 VAC 70 light bulb could be lighted (with one wire connected to the earth) by the left and middle phases but not the right, although quite properly there were essentially 220 VAC between any two phases. There is a neutral wire in the bottom of the circuit breaker box but it was cut off, as would be expected in a delta configuration.

b) Outside the west wall of the Iono (essentially in line with the interior circuit breaker box is a hole in the ground housing the junctions of left, middle, and right phases and neutral wires to main feeder wires as well as taps of two phases seemingly going underground to the large fiberglass sphere. Clearly an explanatory diagram of the splicing/connecting done in this box would be helpful, but I do not recall any shared comment ?that somebody tinkered with the wiring system?.

c) I believe Ms Genie pointed out to me where a special earth electrical-ground was made which had a pipe through which water was periodically poured. I did not ?understand? the water additions, and I asked Fr. Badillo if he knew something about the special Iono ground. Fr. Badillo related that although he personally never saw the ground system, Fr. Hennessy fashioned a ground in the shallow earth of MO by digging a hole into the adobe about a meter deep, then with copper plates surrounded by charcoal, and salt fashioned a ground. Fr. Badillo commented that in all the years of his Ionosphere work Hennessy?s electrical ground gave no problem.

d) To supply the RP with ?safe? power we used the two phases not connected to earth, and then we used our own simple ground for the RP case/chassis. Except for a faulty keypad that is humidity sensitive, the RP ran properly and repeatedly on the Iono from then on.

6) Further comments by a non-electrical engineer:

a) I believe the earth-pinned phase of the MO delta configuration needs to be analyzed. In the case of a lightning strike near the pinned point it would seem that the pinned phase would assume the potential of the lightning.

b) The location of the pinned phase, if deemed by professionals to be necessary, would seem to necessitate shutting down completely each distribution circuit (Annex, Radio, Seismo, and Optical) in order to track it down. Fr. Badillo said that originally MO was entirely 110 VAC so the neutral (grounded) phase was once ubiquitous. Perhaps there is some heavy transformer still connected to one phase and to the neutral?

c) I wonder what the salt-water has done to the copper plates used in Fr. Hennessey?s original earth?

Sorry for the lengthy read.

Thanks for listening.

Fr. David Skelskey, S.J.