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Contactors and relays |
Contactors Switch heavy amp loads on and off | |
Larger image 2-pole 30-40 amp 2" x 2.3" x 2.6" high 3-pole 50-60 amp 5" x 3.75" x 4.1" high |
2-pole
40 amp contactor With removable dust cover on top. Select voltage needed to control coil. 1) Contactors are rated with 24, 120, 208-240, 277, 480 volt coils. Using wrong coil voltage will cause problems. Undervoltage will cause contactor to chatter and can damage load. 2) Contactors are also rated by amperage Selecting a contactor rated for more amps is better, so using 40 amp contactor for 30 amp load is fine. 3) Contactors are either 2-pole for 30-40 amp or 3-pole for 50+ amp. Selecting 3-pole 50-60 amp contactor, 75-90 amp contactor remember that contactors become larger and require larger enclosure. Buy 2-Pole 40A resistive 120Volt coil 40 amp 240Volt coil 24 volt coil Packard contactor Mars 2-pole and 3-pole contactors Rheem HVAC replacement contactors 50 amp contactor 60 amp contactor Resources: Fasco info sheet Packard .pdf 3-pole contactors Mars-Contactors-tech.pdf MARS_780_spec-sheet.pdf |
Larger image What is a contactor? Contactor is a switch. It is rated for high amp loads. High amp causes heat. Heat will damage regular electrical parts. Timers and wall switches can be damaged by high amperage. Each switch and timer has amp rating. Contactors are rated for more amps than ordinary wall switch or timer. The electrical circuit lasts longer when a contactor is used because contact points on a contactor are designed to switch high amp loads without melting or being damaged by heat. The electromagnetic coil can be switched on-off using ordinary wall switch or timer. When voltage is applied to coil, then contact points close, and heavy amp circuit turns on. This lets you control heavy amp loads using ordinary wall switch or timer. |
2 pole
contactor Each contactor has amp rating: this is the number of amps that can be safely switched on-off by the the contactor. Each contactor has coil voltage rating: this is the voltage needed to operate the switching coil. Coil burden or coil VA on a 40 amp, 2-pole contactor is 7.3 Watts, inrush is 27 Watts. Life expectancy <> 200,000 operations Resource: Life expectancy of Siemens definite purpose controllers Contactor dimensions |
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1-pole contactor Only leg is turned on-off, while other leg is continuously connected Buy: Single pole contactors at Amazon |
3-pole
contactor For 30-90 amp loads For coil voltages: 24, 120, 208-240, 277, 480 volt Control 3-phase circuit with contactor Contactors are either 2-pole for 30-40 amp or 3-pole for 50+ amp. Selecting 3-pole 50-60 amp contactor, 75-90 amp contactor remember that contactors become larger and require larger enclosure. Resource: 3-pole contactors What is 3-phase How to wire 3-phase timers and contactors How to convert 3-phase water heater to single phase |
Z-wave
contactor 30 amp, Selectable voltage: 120, 208, 240, 277 volt Operate DPST or 2 x SPST contactor with z-wave Two sets of contacts can be operated at same time, or separately. So you can control different voltages at same time. Buy: Intermatic CA3750 GE Zwave Zwave Hub Resource: How to wire and set up CA3750 How to wire GE zwave |
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2-pole
40 amp contactor in 6x6x4 enclosure Using #8-32 x 3/4" bolts Install contactor at angle leaves room for wire This is DPST contactor Double pole, single throw. So the contactor is 2-pole. It can turn off 2 wires. And single throw because both poles are on-off at same time. So you can switch both wires in 240 volt circuit. Buy Metal Bud industries 6x6x4 Nema 3R Outdoor box Hinged door/ 6x8x4 Polycarbonate enclosure Bud industries boxes at Amazon Arlington boxes at Amazon Resources: How to wire contactor for water heater Enclosures |
Connect wires to contactor Use correct size large screwdriver or #3 square head driver. Use T handle driver instead of cordless tool for best torque without damage Cordless driver can sometimes crack apart circuit breaker, outlet, switch etc, and might slip from screw before wires are firmly attached. Buy: Square drive set T handle nut driver Ratchet screwdriver Resources: Safe electric wiring Color code wire Extension cord code |
Wires connect to contactor Hot and neutral can connect to either side. Buy: 120Volt coil At Amazon 240Volt coil At Amazon Mars 2-pole and 3-pole contactors at Amazon Resources: Furnas cross reference Siemens cross reference 3-pole contactors |
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Terminals Buy: Terminal kit at Amazon with crimp tool Electrical terminals at Amazon Blue 14-16 gauge female terminals 20 pcs at Amazon Yellow 12-10 gauge female terminal 16 pcs 360 pc assortment at Amazon 520 pc assortment at Amazon Resource: More about #10 & 14 female terminals |
Larger image Neutral required: Installing wall-mounted timer or home automation plan draws Black Hot and White Neutral from any nearby outlet box. Applies to all 120 volt programmable timers, countdown, wifi and zwave home automation devices. Rule of thumb: Neutral wires are white and usually covered with wire nut and pushed to back of box. An outlet box will always have Hot and Neutral, and Switch box will always have Hot but not always Neutral, and Ceiling box with light will always have Neutral but might only have Hot when light is on. Modern wiring code requires each box to have both Hot and Neutral. Resources See installation Color code for wire Buy 240Volt coil 2-pole contactor Bud industries 6x6x4 Nema 3R Outdoor box Hinged door/ 6x8x4 |
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Connect modular timer to
contactor Resource PB series and other timer modules 24 volt programmable timers |
Sprinkler
timer connects
to contactor Convert 24 volt sprinkler timer to 120 volt Resource: How to wire Intermatic sprinkler timers |
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3-pole contactor Control 3-phase using contactor Select: 3-phase contactors Resources How to wire 3-phase timer How to wire 3-phase What is 3-phase Compare 40 amp box timers Compare all box timers |
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Override T104 timer Resources: T104 timer wiring T100 series timers Compare all box timers Pool control centers Freeze controls |
Larger image Larger image 2 Control motor with 2 switches Same wiring diagram applies to single-pole switch Buy Contactor with 240Volt coil 240Volt coil Start winding pulls more amps than switch can safely handle. Over time, the switch will fail. Contactors are rated for heavy amp loads, with expected life of millions of operations Resources: Delay timer for motor or pump Control motor with 2 switches or timer Motor troubleshoot and resources |
Life expectancy of contactor <> 200,000 operations Contact points stick sometimes Solution: use nail file or emery board or folded sandpaper to clean off points. Electrical formulas |
Relays Contactors switch heavy-amp loads on and off Relays are generally for lighter amp loads but have additional function letting you switch between two different loads | |
Open frame power
relay with enclosure 30 amp, 2-pole, SPDT relay.... different from DPST contactor. Both perform same job. Both have 2 sets contacts. Open frame relay SPDT has extra set contacts so a second load can be turned on-off exactly opposite from off-on other load. 12-24-120-240 volt coils/ 30 and 40 amp models Note that a 30 amp
power relay, or switch, or contactor has safe maximum 80% rated value,
or 24 amps. For 30 amp circuit, must use 600 volt, 10 gauge solid
copper wire. Never undersize wire or use extension cord for permanent
wiring.
Buy from my affiliate links Magnecraft box and cover Siemens power relays Schneider W199 relay NTE open frame relays Packard DPDT fan relay Tyco open frame relay Contactors/ reliable for heavy amp loads 15 amp Relays for loads up to 10 amps Resource: Open frame wiring DC relays for solar panels Reverse motor using DPDT relay Control motor with 2 switches Start two motors at different times How to reverse motor with switch Relays for DC motors and solar panels |
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Omron LY23 AC Model
terminals/ back to front:
7-8 magnet terminals (turned opposite direction from other pins) 5-6 common terminals 3-4 NO normally open terminals (power is off when relay off) 1-2 NC normally closed terminals (power is On when relay is off) Load rating 7.5 amps AC 900 watts incandescent @ 120V 1800 watts incandescent @ 240V 1/4 Hp motor @ 120V; 1/2 Hp @ 240V |
To
reverse operation of photo-eye So Load comes on during daylight hours photo eye connected to DPDT relay 30 Amp relay x 80% = 24 amp max up to 2880 watt @ 120V or 5600 watt @ 240V 30 amp 10 gauge wire up to 2 Hp @ 50' or 1.5 Hp @ 100' @ 120V See load charts Use Omron 120volt LY2-AC 8-pin relay for 7.5 amp. (Note that the LY2 and LY3 15 amp relays are rated 10 amps for 2 and 3-pole relays. And 5 amps for LY4 4-pole relay.) 7.5Amp Omron 30Amp DPDT Buy Omron LY2 at Amazon / Choose 120Volt coil 30 Amp relay at Amazon 12amp DPDT Packard at Amazon Resources: Omron relay/Page 450 / pdf |
Reverse
motion sensor so
Load turns OFF Buy: Motion sensor at Amazon Resource: How to wire motion sensor Fuseholders |
Power relays LY2 relays etc Resource: LY2 .pdf | |
Uxcell LY2
relay/ 10 amp
relay with base ... fits din rail With these small 10 amp relays, do not put 2 wires under same screw plate ... use individual wires joined by twist on wire connector. It is against code to use 100-300 volt extension cord as permanent wiring. Code requires ordinary 600 volt electrical wire as seen embossed on wire sheathing. Recommend using solid copper wire under screw plates, and not stranded ... motor loads can cause stranded wire to get warm enough to splay apart and loosen under a screw plate. Of course all electrical connections (relay etc) must be contained inside electrically-rated enclosure (not homemade wood box etc) ... with a matching cover applied. Buy: Uxcell 120 volt coil Uxcell relay 6x6 x 4 enclosure 4x4 x 4 encloure Tapered drill bit Resource: Enclosures |
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DPDT
Switching relay 12 amps @ 120 volt, 6 amps @ 208-240 volt/ 3/4 HP White Rodgers, Packard, Emerson, Edgewater, Mars, Honeywell, Jard, RBM etc Buy: Packard DPDT fan relay Resource Mars-relay.pdf mars-general-purpose-switching-relay.pdf Packard-switching-relay.pdf |
Solid state relay/ SPST Check for AC-AC input-output DC input to AC output is most common Buy: AC to DC/ AC to AC AC to AC 100-240Volt AC input / 20 amp/ at Amazon Relay safety cover Heat sink Resource: Electromechanical relay vrs solid state relay/ pdf convert AC water heater to DC/ high voltage Convert AC water heater to DC/ low voltage |
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SPDT model C shown/ 30 amp NO terminal/ 20 amp NC @ 277 V Also available SPST model A/ 30 amp NO terminal @ 277 V Base 1.08" x 1.98" / 1.09" high |
Zettler
30 amp miniature power relay Coil voltage 120-240 VAC / also DC ratings Contact ratings 277 volt AC/ 28 VDC Use quick connect terminals Buy: Atwood miniature relay 120Volt SPST miniature relay at Amazon Zettler relays at Amazon Resources: Zettler relay wiring Override thermostat with programmable timer Manual/ spec sheet Terminals |
250VDC 25 amp 400VDC 200 amp |
DC power relays Full on-off contacts/ 12 or 24 volt DC coil 250 volt / 25 amp DC load 250V x 25 amp = 6250 watt Connect 12 or 24 volt DC to terminals 3-4; Connect load to terminals 1-2 Buy: Electromechanical DC-DC G9EB-1 relay G9EB-1-B-DC24 24 VDC coil and 400 VDC/ 200 amp contacts Fuseholder Resources: DC relays for solar power Omron-DC-DC-relay-Datasheet Omron DC-DC pdf DC power relay spec sheet |
Coil 12-24 VDC Load contacts 26 VDC 40-50 Amp |
12
VDC 40-50 amp DC power relay Buy: W199AX-3 relay W199PX-13/ 50 amp at 26 VDC = 1400 watt X199 Magnecraft relay Magnecraft W199 DC relay Resources: Magnecraft relay / pdf Resource |
Enclosed relays/ Functional
devices Buy: Enclosed relays at Amazon 3PST AC-DC at Amazon Functional relays at Amazon |
Amp
relay When amp exceeds amp set point, the relay activates 120 volt circuit. Recirculation pump is 1/25 Hp or 30 watts divided by 120 volts = .25 amp\ 1 Hp motor is 750 watts divided by 120 volts = 6.25 amp Use relay to control contactor when load exceeds 50 watts Use to activate duct booster fan Take off bracket and install bracket around a control wire that carries amperage When amperage flows across line, the Aprilaire relay activates... and closes circuit going to 120 Volt load... such as indicator light... or another relay etc... the indicator light turns ON. Wrap the wire multiple times to increase measurable current Use a current transformer to reduce current Buy: Amp relay/ CSS or current switch/ current transducer Buy: Aprilaire relay 4 amp at Amazon Suncourt relay 1.2- 40 amp at Amazon Louensy 0-200 amp johnson current sensing< Low amp current indicator Current sensing relays Current sensing switch Current Transformer< Current sensor module Resources: Aprilaire manual .pdf Johnson control amp sensing switch/ pdf NK technology AC current sensing switch/ pdf |
Buy: 120 volt Pilot light at Amazon 120-240 pilot light indicator light 120v indicator light 120v Resource: How to wire water heater pilot light Add to water heater indicator light page: Low amp current indicator |
What is 3-phase electric: power plant to end user |
Buy
from my affiliate links every time/ thanks: Amazon ''As an Amazon Associate I earn from qualifying purchases'' Enter Amazon from any link on my site, fill cart with any item ... purchases pay small commission E-mail: geno03245w@gmail.com My response might end up in spam folder, check email folders |