Re: Is this sentence about AC voltage okay

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Re: Is this sentence about AC voltage okay

Irwell	07 Jul 2009 21:19
> You need to get into the 20th century! The 22nd century of the Anno Domini era will span the years 2101–2200 of the Gregorian calendar. Wiki

contrex

07 Jul 2009 17:55

> Unless your aim is to make a really loud buzz (which, granted, was the
> object of most of my childhood projects involving relays), it isn't
> going to operate in a useful way on any AC voltage without being "set
> up" in some way with a rectifier and a capacitor.

You need to get into the 20th century! There is such a thing as an AC
relay. The basic difference between AC and DC relays lies in the
armature and magnet core construction. The armature and magnet cores
of an AC relay are made up of laminations, and those of a DC relay are
of solid material. The use of laminations in an AC relay reduces the
heating due to eddy currents. In addition, an AC-powered relay has
what is known as a "shading coil", which is a shorted turn on the
relay's solenoid. A current is induced in this shorted turn which is
90 degrees out of phase with the main coil's current, and provides
just enough magnetic field to keep the armature engaged during the
zero crossing of the current in the main coil. An AC relay will be
designed for an approximate frequency of alternating current. Thus a
device designed for 50/60 Hz will not be suitable for the 400 Hz
current found in aircraft.

Glenn Knickerbocker	07 Jul 2009 17:05
> 2. Relay coils are "rated" for a particular voltage, not "set up". Unless your aim is to make a really loud buzz (which, granted, was the object of most of my childhood projects involving relays), it isn't going to operate in a useful way on any AC voltage without being "set up" in some way with a rectifier and a capacitor. ¬R

contrex

07 Jul 2009 07:12

> So, if relay B's coil was set up to run on, has been running on 16
> volts AC, is there any chance it can run just as well on 24 volts AC?
>
> Is this sentence okay?

My sugestion:

If relay B's coil is rated to operate on 16 volts AC, is there any
chance it can be operated just as well on 24 volts?

1. I would question the need for "So" at the beginning.

2. Relay coils are "rated" for a particular voltage, not "set up".

3. "Operate" rather than "run".

4. The second "AC" is redundant.

5. "has been running on" is not needed.

6. If you use a relay coil rated for 16 volts AC on 24 volts you would
very probably drive the core into magnetic saturation and it would
overheat. If this situation were prolonged there would certainly be a
reduction in service life and possibly a fire risk.

mm	05 Jul 2009 19:18
So, if relay B's coil was set up to run on, has been running on 16 volts AC, is there any chance it can run just as well on 24 volts AC? Is this sentence okay? Signature Posters should say where they live, and for which area they are asking questions. I have lived in Western Pa. 10 years Indianapolis 10 years Chicago 6 years Brooklyn, NY 12 years Baltimore 26 years

Re: Is this sentence about AC voltage okay

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