Faulty Canadian Mobil-Directos

[uncommonsense]

Hey there. So interesting find. I was doing research for the Allertor Timeline thread and stumbled on this gem. The actual link is behind a paywall, but this image showed up in Google Search. The caption to the photo says it all.

Very interesting. I had no idea the Mobil-Directos were wrought with issues. Anyway, neat find and thought you all would like it. I just wish I knew where the caption's info was sourced from.

Also interesting to note the MD was available with a coding mechanism (the long fabled yelp brake perhaps?)

[holler]

Very interesting, wonder if it was a dealer problem, reliability problem, or coverage problem?

[Mark N]

Whoa, nice catch! Perhaps the Multi signal model was just an alert button or an added on/off timing signal. Still could be the yelp though. I think the problem was reliability (I think one of the reasons for ACA to switch to fiberglass was the steel MD had problems with matineance). Nonetheless, an interesting find! I

[Siren_Dude]

I have a bunch of old archive stuff on this. I'll try to find it and let you guys know. I know they replaced tones of rotors and other mechanical elements, not sure from coverage or reliability.

[holler]

Wonder if was because of the freezing?

[coastalsyrolover]

So could the MD actually do yelp? And how in the heck would it do that? Like how would the brake work to instantly stop without breaking anything??

[DJ2226]

[quote="coastalsyrolover"]So could the MD actually do yelp? And how in the heck would it do that? Like how would the brake work to instantly stop without breaking anything??[/quote]
I believe it was done with a motor starter that reversed the phases on a 3 phase motor.

[Siren_Dude]

Found a decent amount of information, all of this is only from the Toronto system so who knows what else was happening elsewhere.

-New rotor and stator assemblies for all MD's to increase range of siren, pitch and frequency. Was completed in Toronto in 1962
-Government wanted all to be replaced which was a total of 252 in the 1960's
-Susceptible to freezing during winter
-Slip ring failures
-Collector ring assemblies did not meet CSA or Ontario Hydro minimum requirements, all were replaced

I have a large engineering report from the Toronto system also which goes into detail (alot of detail) about the failures. Alot of them were from electrical issues and not being installed properly. They had wrong fuse sizes, they would blow out during wailing cycle or attack. The installed 10KVA transformers were being overloaded by 50% at full load and even more during wailing cycle. That's because the motor draws the current of a 15HP motor and not the rated 10HP. They recommenced a 15KVA transformer. No one calculated for voltage drop so they replaced the 12 gauge to min 8. The capacity of overloads or heaters was to low, they increased but they cancelled them all together. Over all the beginning of the system was plagued with issues and for that matter for there entire life, some being mechanical but alot was due to sloppy instillation. I have no information about the suing part but I can imagine some of this has to do with it.