🚀 go-pugleaf

"DaveC" <anon@example.net> wrote in message
news:01HW.B75F3E26002EF2D601D72810@news.dnai.com...
> A friend has a custom woodworking business. He has several 220 3-phase
> planers, sanders, etc. and a few 220 single-phase also. The shop is
equipped
> with a dust collection system (basically a large vacuum cleaner) that is
> plumbed to most of the tools. Most of all of these tools are on their own
> circuit breakers and wire runs. One small 110 vac saw is on a standard
shared
> plug-in 20 amp circuit.
>
> The fire inspector wants him to wire the dust collector such that it turns
on
> whenever any of the floor tools is turned on.
>
> I'm now sure how to sense the current in these circuits. Is there a
standard
> remote-turn-on relay that is used in circumstances such as this? Is there
a
> simple way to build a circuit to sense the tool startup? Controlling the
dust
> collector power seems pretty straightforward (220 single-phase).
>
> Any suggestions would be greatly appreciated.

According to the pros who post on ALT.HVAC there is a relay out there that
you run a conductor through and when current flows, the relay closes.    The
relay is used to sense when a multispeed fan has been turned on.

Unfortunately, I have not seen this relay in the Granger catalog.

BUT, you would use one of these relays for each sawdust producing device and
wire the contacts in parallel.

OR

You can just wire a "regular" relay coil of the appropriate voltage across
ONE of the hot lines to each three phase load and to each regular (single
phase) load.    As above, you put the contacts in parallel to operate the
vacumn motor.

The "regular" relay is the way to go if your motors all operated in a single
speed mode.

The X10 folks market a current sensor but by the time you add the extra
stuff you are better off with a $10 relay per sawdust producer.

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> Thanks,
> Dave
> --
> Dave Carpenter
> Sound Logic
> voicebox@NOdnai.com
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