today the elevator room on the roof is all relays, looks like a
frankenstin set from the 50's wouldn't be surprized if the relays are
actually from 50's either

my antenna is mounted on the wall (brick) of this room

currently i don't get any noise (electricial)



Just found out the building is thinking of adding new elevators and
modern controlers

so now i wonder, should i suspect that they are all rf tight in metal
housing's or a rf nightmare?


anyone have any experience w/how much 'noise'/hash they might throw ooff?

tnx

m

On Tue, 04 Apr 2006 23:21:17 GMT, ml wrote:

anyone have any experience w/how much 'noise'/hash they might throw ooff?

Hi Myles,

Most controllers I've designed with were always "zero crossing"
sensitive. That means they did not add RF trash by switching loads at
high (or even modest) voltage levels. This is not to say when they
turn off the load as some controllers are proportional (using a part
of the voltage cycle).

For motor control, I have had to use very, very fast servos which
could tolerate an overvoltage of 10:1 of its usual rating (hitting a
10V servo with 100V for instance). I didn't give much thought to the
hash created because this was in a printing plant where I had to
accelerate a page of paper in milliseconds (takes quite a bit of power
to do this).

Do a noise survey with a portable SWL receiver, and visit a lot of
buildings with elevators. You can do a dnoise/dz sweep as the
elevator climbs.

73's
Richard Clark, KB7QHC

In other words, you won't really know till the new system is
actually installed. That means a 50/50 chance for or against.
'Doc

In article ,
Doc wrote:

In other words, you won't really know till the new system is
actually installed. That means a 50/50 chance for or against.
'Doc

thanks all, that responded

guess i'll have to wait and see,

i wouldn't mind doing a survey however i'd have no way to really know in
the residential area i live which building have electroic elevator
controllers or not , can't tell from outside and can't really poke
around


OK i guess a better question might have been:

so if the controllers give off bad rf

what is the best way to 'shield' those boxes so they won't bother my
antennas outside the room?

presume that i can ground the cabinents myself if they are not already .



thanks

Having spent 10 years in the elevator industry, you'll find that new
equipment is mostly solid state with relays only controlling the safety
circuit and motor controls. The controller is encliosed in a steel cabinet
and as a result is ussually well shielded.

That being said, you did not indicate what type of drive system will be
installed, SCR (DC motors), AC V3F Drive Etc or will the current drives be
left as is. These could potentially be a source of noise depending on the
manufacturer. Motor/Gen set (older DC drives) could be very noisy when the
brushes are worn. Newer AC V3F drives could be noisy when DC injection is
used for braking and holding the elevator at the floor (noise from the motor
windings as they vibrate at who knows what frequency).

Most mechanics will be willing to share the info when you see them, coffee
helps.

Remember the the elevator guys don't mind the sudden stops only the little
jerks in between. Hi. Hi.

73's
Guenther VE3CVS


"ml" wrote in message
...
today the elevator room on the roof is all relays, looks like a
frankenstin set from the 50's wouldn't be surprized if the relays are
actually from 50's either

my antenna is mounted on the wall (brick) of this room

currently i don't get any noise (electricial)



Just found out the building is thinking of adding new elevators and
modern controlers

so now i wonder, should i suspect that they are all rf tight in metal
housing's or a rf nightmare?


anyone have any experience w/how much 'noise'/hash they might throw ooff?

tnx

m

The new elevator that was installed in my building here at the university,
puts out a large amount of noise on the AM broadcast band every time it
moves. I believe they are doing some sort of phase control on the motor with
little filtering.


--
John Passaneau
Penn State University
Physics Dept.



"ml" wrote in message
...
In article ,
Doc wrote:

In other words, you won't really know till the new system is
actually installed. That means a 50/50 chance for or against.
'Doc

thanks all, that responded

guess i'll have to wait and see,

i wouldn't mind doing a survey however i'd have no way to really know in
the residential area i live which building have electroic elevator
controllers or not , can't tell from outside and can't really poke
around


OK i guess a better question might have been:

so if the controllers give off bad rf

what is the best way to 'shield' those boxes so they won't bother my
antennas outside the room?

presume that i can ground the cabinents myself if they are not already .



thanks