how to wire motion sensor to a dtds relay
how to wire motion sensor to a dtds relay
(OP)
I am looking for a "small" motion( that is movement not motion) sensor that could pull a set of contact in and to operate a small motor. This must go thru 110v switch and when the sensor is not in use the switch could turn on and off the motor. The max. load would not exceed 400w. I would like it all to fit in a 1 1/2" x 3" x 2". The sensor would not be used only about 5 time per year for the effect and if I could put a min motion amount for the switch to operate, it would be equal to 1.0 earthquake. This would not cause the switch to operate due the the other equipment in the area. This is a project I am working on for the studio. Sorry for the ruff discription, but I am not an electrical enginner.Thanks for any help.
Gregg
Gregg
RE: how to wire motion sensor to a dtds relay
The load you need to switch is too large for the sensor to switch directly (depends on the sensor you select). In any case, since you are running a motor with this then a contactor/starter should be used (overload protection is required so get a starter (contactor with overloads)) with a 120VAC coil. If the coil is 120 then you can use the same power that feeds your motor to run your controls (sensor and starter). As far as turning the motor on with a switch when the sensor is off, you could just use a properly rated switch (120VAC with current rating equivalent to the starter coil current) in parallel with the rest of the controls. Granted a 4-20mA signal is not adequate to pull in the starter so if 4-20mA is used some other circuitry will have to be made.
RE: how to wire motion sensor to a dtds relay
RE: how to wire motion sensor to a dtds relay
To answer your last question; I would say the 4-20mA would not drive your lights directly. Perhaps you mean the 4-20mA would pull-in a relay that would in turn energize your lights and/or motor. You could play with the 'pull-in' voltage rating of the relay you select to coordinate with the output of the sensor. You need to check on the maximum load of the 4-20mA sensor to make sure it has enough voltage to supply the load with 20mA. Most 4-20mA equipment the max load is around 500 ohms. So if the sensor is supplied with say 12VDC and you want to send 20mA into a load the maximum load will be 12/.02=600 ohms or less.
RE: how to wire motion sensor to a dtds relay
RE: how to wire motion sensor to a dtds relay
I am not that familiar with mercury switch operation but I assume this is what is giving you the movement indication. If you review the data sheet for the one selected it will quickly let you know if it is rated for that kind of current. If it is not, just use a relay. The sensor would energize the relay and the relay would turn on the lights. You might also choose to have the standard switch energize the coil of the relay as well.