Mamac Current Sensing Switch/Switches, CT-800/CT800 NEW on Ebay

jwilson56

jwilson56

Senior Member
Came across this item while looking for relay based current sensors to replace my CD Magnetics/Powerflash setup and tie it into my Elk.

This is a good deal on these...

Here is his description:


This item was acquired at a salvage freight sale recently, and they are brand new in the original, unopened factory bags. The cheapest I found them online was $25 apiece, and we only received one small box, so they won't last very long.

Best I can tell from reading about them, you run a wire or cable through the center hole of the switch. When the switch senses current traveling through the cable, the internal contacts close and connect the two wires attached to the screw terminals on top of the switch. The really neat thing is that the switch is passively powered by the flow of current through the center hole, and there is no current loss at the terminals as a result of powering the switch. Moreover, they can use either AC or DC voltage through the hole to power the switch, and the switch can control a .3 amp AC or DC load at any voltage up to 135V. These would solve a lot of voltage and amperage compatibility problems and prevent dozens of trips back to the shop to get parts. Not to sound like a snake oil salesman, but you might say they are "good fer what ails ya."

According to the calipers:

Length of mounting base: 3.500"

Length of switch body, excluding mounting base: 2.398"

Overall width: .940"

Inner core diameter: .730"

Mounting holes: .188" (3/16") spaced 3.020" OC (on centers)

The labels read as follows:

1A SETPOINT 0.3A @ 135 VAC/VDC MAX CT-800
MAMAC SYSTEMS
Minneapolis, MN 55344
MADE IN USA
CE (certification mark)
UL UL (certification marks)
id LISTED 5T44

MAMAC SYSTEMS
Minneapolis, MN 55344
MADE IN USA
LISTED 5T44 c (UL certification mark) US Ind. Con. Eq.


According to the manufacturer:

MAMAC CURRENT SWITCHES

Easy to install

Small size, built-in mounting flanges, and topmounted terminals

Intelligent design

-- Self-powered
-- Solid-core
-- UL listed and CSA certified
-- Compatible with EMS, SCADA, and automation systems

Broad application

CTs monitor all types of fans, pumps, heating elements, motors, lamps, and relays

The CT 800 Series provides a wide selection of current switching options in a small and durable solid-core design. These self-powered switches can be easily hung or tied directly to cables or wires. All models are UL listed and CSA certified and are compatible with EMS, SCADA, and automation systems. The CT current switches monitor all types of fans, pumps, heating elements, motors, lamps and relays.

Specifications -- CT-800

Monitored AC Current: 1 to 250 amps
Maximum Currents:
250 amps maximum continuous
500 amps maximum for 6 seconds
1000 amps maximum for 1 second
Switching Characteristics: sensor trips at 1 amp
Switches up to 0.3 amp continuous, 120 VAC or 120 VDC with zero offstate leakage
Contact is not polarity-sensitive. Switch can be used for both AC and DC circuits
Response Time: Depends on how much greater the load is than the setpoint. Motor-starting surges up to 6 times FLA can be as low as 0.2 seconds. If the setpoint is very close to the load, response time will be longer.
Isolation Voltage: UL/CSA approved for a withstand voltage of 1240 VAC
Temperature Range: -50C to 65C (-58F to 149F)




http://cgi.ebay.com/Mamac-Current-Sensing-...id=p3286.c0.m14
 
Those look pretty cool. I don't think I have a need for one, but I can see their benefit.

FYI - these don't look like they are split core, so just make sure the power plug is small enough to go through the hole, or that your power cord can be disconnected and feed through the hole.
 
sounds like a good way to see if the tv is off or on... connect the relay back to the global cache and it will tell your automation system what the tv status is (assuming the tv draws under 1A while in standby).

or i guess whether the washer and dryer are still going... would be good for a whole-house reminder that the dryer is finished and get the damn clothes out of the dryer already, wife.
 
Ok a couple of technical items if you decide to use these.

First you must only put one leg od a cord through the hole to have it detect current. I often buy a cheap short orange extension cord and cut into it carefully and separate the wires and cut the black wire then wrap that wire around the hole then solder it back together.

Second.... most current devices like will multiply the current sensing for each turn of wire you wrap into the hole.

I use these for the dryer as well as anything else you want to monitor its power state. I have used the CR Magnetics ones in the past with a Powerflash X10 unit as it put out AC voltage. These however have a built in relay. In fact the entire unit is self powered. So you only need to wire it into anything that needs a closed contact such as an Elk zone or an Ocelot input.

Yeah you can't beat the price and his shipping is some of the lowest I have ever seen on Ebay.
 
Well I can't see anyone who is really into home automation not needing some of these...

BTW the guy said in an email to me "we have an outrageous quantity of various sensors, switches, relays, connectors" so I will keep an eye out for other goodies.
 
Squiddy said:
That auction has ended but he put up another one at: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...em=300264084838

I just bought 4 of them. 2 left!
Click to expand...


I posted the link for the new auction above... but as you can see the Cocoontech effect is amazing.


BTW I used a couple of these with the NX-650 for a wireless Elk solution to detect current. It sure beats wiring in an old house like mine. Just hook across the internal contacts and disable the built in reed switch in ElkRP.
 
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