Questions tagged [contactor]

A contactor, like a relay, is an electrically controlled switch. Contactors generally have higher voltage and current ratings than relays, but the ratings overlap with no specific dividing line. Contactors are intended to control the power supplied to motors, electrical heaters, groups of lights and other loads that require an undefined level of "high power." The word "contactor" is essentially defined by its use in product literature.

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Need help figuring out 8 heater PID controller circuit

I am building heater controller system for 8 heaters using PIDs and contactors. Heaters are divided into 4 groups i.e. 4 pairs of heaters. Each group has its seperate thermocoupler, PID and contactor. ...
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Why do contactors have lower withstanding current for signaling than power circuits?

Suppose this contactor by Schneider LC1D115. I don't understand why it has a lower withstand current for signaling circuits when it can handle 10X the amount of current for power circuit on the same ...
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67 views

Mains safety shutoff

I have a problem. I have a sensor in a piece of equipment that needs to switch off that equipment if it detects a dangerous gas. The equipment must remain off until a manual reset is applied. What ...
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How do I protect a contactor in arc weld circuit from wear?

I have a load banker (a toaster run by a 100 - 800 amp 10 - 40 V DC welder with non contact amp and volt sensors built in). I am trying to make an arc flash prevention unit for it. Relay control with ...
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How do you prevent feedback in a relay or contactor (120V coil, 120V contacts) when coil and contact are both connected to one source?

I have a 2NO 2NC 120V coil, up to 400V contacts contactor. (Electrodepot 934022) I need to power both the coil at 120V and the contacts at 120V from the same source. Manufacturer says this is not ...
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Detect the state On/Off a DC 12V single coil latch relay

A LiFePo4 charging/discharging circuit (12 V, 200 Ah, 100 A max) is protected by a single coil latching relay with manual override. This relay is controlled by an ATMega328 (through a FET with flyback ...
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Problem figuring star delta starter circuit

I know the basic functioning of star delta motor starter configuration but kind of stuck on my current project which uses old L&T starter panel. I can't figure out the terminals like A1, A2 (coil ...
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Three Phase IEC Equipment Ratings

Sometimes, when checking datasheets of Three Phase equipment, specs for "220-240 VAC" and "380-440 VAC" appears, as for these Mitsubishi Contactors Catalog AC-3 Power Ratings. ...
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71 views

When does an electrical product get an RU (Underwriters Laboratories) certified mark?

If you take an example of contactor, it can be used in residential, industrial, electric vehicle applications etc. Let's say the contactor has passed the UL standards corresponding to the industrial ...
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Duration of inrush current for high pressure sodium lamp with electronic balast

I'm trying to find reliable information regarding the duration of inrush current for high pressure sodium lamps with electronic ballasts. This document states that: "In reality, due to the ...
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MOSFET instead of a contactor in Battery Management Systems (BMS)

For relatively high current systems (>50 A) with Lithium based batteries, I've seen that usually BMS controls the output with contactors for both main supply and precharge. Why not use a high ...
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41 views

Isolated Triac Driving on Low RMS Current Load

I'm trying to drive a triac to control contactors. Here is the circuit I'm using: I have 3 different contactors which has series resistances like: 200R, 550R, 1.4k When using contactors with 200R and ...
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Estimating the power usage of a contactor

I'm trying to figure out the energy cost of the Hartland HCC family datasheet of contactors, in an application where they are pretty much active (contacts closed) 24/7. I understand that in an AC ...
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42 views

Contactor rating with capacitive load, how to compute the maximum allowed capacitance?

Considering this: simulate this circuit – Schematic created using CircuitLab V1 is a beefy battery - it will happily provide 1000A or more; RLY1 is a beefy contactor, the LEV200 series, rated ...
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109 views

can I rewind a 220 volts coil into 24 volts?

My machine's magnetic contactor needs replacement but it's quite difficult to buy a 24 volt coil magnetic contactor. Can I purchase a 220volt coil magnetic contactor and rewind the 220v coil into 24 ...
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155 views

Help with high-current DC switching

I need to remotely switch a 48 V battery that is supplying a 15 A load (which is slightly inductive), as part of a low voltage protection circuit for a PV solar system. Am familiar with the challenges ...
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Meaning of symbols used in ABB contactor circuit

The picture below is a power circuit for a direct-on-line starter, given in any ABB catalog for contactor. Q1 is a manual motor started with overcurrent protection. My question is What is the meaning ...
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20A 4P Contactors or 25A TP Contactors

I am replacing a power distribution box that has 125A inlet and 16 No. 16A outlet sockets with earth leakage and overcurrent protection (16 No. 25A 30mA RCCB and 16A MCBs). We are fitting contactors ...
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79 views

How to size The DOL Motor Starter knowing that the motor is a part winding start motor

I have a BITZER compressor type 4GE-23Y-40P, with a part winding start option of the motor Nennspannung = nominal voltage = 380-420 Frequ = frequency = 50 Betr. strom = maximal operating current = 43....
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How does a contactor holding work?

If I'm correct, AN in below picture is an electromagnet. When the switch S is pushed, the electromagnet AN connects L1 to T1 and L2 to T2. When the switch S is released, the electromagnet AN ...
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170 views

High voltage contactor EMC circuit

I am using a 12V relay to drive high voltage contactors. The contactor coil causes EMC when turned off. I am uncertain of which circuit I should use for reducing the EMC. Is there even any difference ...
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696 views

Using three phase contactor with single phase motor

If using a contactor for 3 phase motors with a single phase motor, can just the hot (120v) line be passed through the contactor, with the neutral and ground bypassing it? I believed the concept for ...
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Unsure if motor starter (contactor + overload) is needed instead of normal solid state relay

I am designing a system with several pumps ranging from 0.5 to 1.5 HP (all single phase) and am unsure of what kind of circuitry I need. I researched different motor contactors and overloads I could ...
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Starter for Sump Pump

I'm trying to determine proper circuitry for starting a sump pump, but am unsure of what components I need. Originally was going to just use a relay, but have read suggestions for contactor+overload ...
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What is the purpose of these coils in contactor auxiliary contacts?

Can someone please tell me what the function of this module, and more specifically, the curley wires on top of this contactor? It looks like the wires go to the same terminals as the main contactor ...
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138 views

\$\mu\$ Symbol on a Relay Module's Nameplate

One of our customers gave us a sample product for inspection. It has a relay output for 220V loads (e.g. fan, bulb, etc.) Just out of curiosity, what is the meaning of the \$\mu\$ symbol here?
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How to control one motor with two float switches

I have 2 tanks , one is under another and hopes to pump from under tank to upper one using a 0.5 Hp single phase motor.By connecting float switches for both tank,can I control the motor to turn on ...
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DC Relay overrated for max. 100ms

In my case I need a relay to switch continous 0.5A at 24V DC, but in time of closing the contacts there will occour an inrush current from the further circuit of 6A, but only for max. 100ms because ...
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31 views

What kind of contactor or device do I need to keep a contactor closed until power draw of the primary circuit is complete?

I have an application where I need to signal a start by sending a 120V signal to the contactor, so it will close a 208V 3 pole circuit. The load on the circuit will run for an unspecified amount of ...
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26 views

Can I use solid state output and relay output with the same components?

So I have a OTB1E0DM9LP Schinder Electric I/O distributed module and I want use it'output to control some 24v electro-valve's and some 24V contactors. The module have 2 Solid-state outputs of 24V 0....
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379 views

Using PID relay to drive multiple contactors

I am a physicist by training but have been tasked with designing a heating controller box for a custom application that will be used in an industrial setting. I would like to make sure that I am ...
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322 views

What is the coil voltage of this contactor?

Sorry for dummy question but I don't know how to identify the coil voltage necessary to activate this contactor? Thank you
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Switching 400V motor with 5V

I'am trying to make an automatic irrigation system using an Arduino, a moisture meter and a water pump. The issue is that I can't figure out whether there is some relay/contactor type component that ...
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216 views

Contactor: when and how to use it

I hope my question is not too stupid. I'm controlling a brushed 48V 50A motor with a motor controller and I use two gel batteries as a power supply. I would like to use a low power signal to switch ...
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What is the max current of this contactor? CDC65-24

I'm attempting to power a 50kW DC Fast Charger with 3 phase 277/480V. It needs ~55kW which is 66A per phase. I'm trying to find a contactor. This one is CDC65-24. It is a 3 pole, 100A continuous. ...
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171 views

Two Switches to Control a Pump

I have a water tank that I want to fill up with a well. I have a float switch at the top of the tank and another float switch in the middle of the tank. What I want to do is have the pump only turn on ...
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778 views

Vacuum Contactor Wiring Diagrams

In reviewing the following wiring schematics for a vacuum contactor, I can't wrap my head around why things are the way they are. Source > Downloads > Catalogues Wiring Diagram #1, Size 4 Contactor ...
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231 views

How to connect voltage protection relay to contactor?

Could you help me connect a voltage protection relay (VPR) to a contactor? I'm not sure how to connect the relay output terminals (NO, NC, COM, etc.) to contactor control terminals A1 and A2 in the ...
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Digital control of contactors

We are trying to control a bunch of 3 phase contactors using an HMI. The contactors' coils are activated by two lines of the 240V 3 phase source (L1 and L2). We are trying to figure out if the ...
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Can a contactor be used as a temporal logic bit as in PLC?

I want to design a control logic circuit using relay logic. I want to have a bit as a marker as in PLC. Can I use a contactor for this function and then use auxiliary coils as a latch as in PLCs.
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Which suppresor device will be use for 2pole AC contactor 240v coil voltage in coil as well as contact side?

I need an AC contactor for a 1 hp motor. For the contactor safety I'm goint to use the suppression device on the both coil and contact side. Please suggest me which suppressor device will be use! I ...
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272 views

How Does Line Frequency Affect Coils of a Contactor?

I am using a generator as my source voltage, which produces 240VAC @ 240Hz. I was planning to use the following contactor from TE: CONTACTOR 4PST 40A 240V In the datasheet it says this contactor's ...
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What lubricant is suitable for switch contact?

I have this expensive DPDT switch (20A 250V 2hp) which the only problem is dirty encumbered inside. The encumbrance is made of carbonized material and some kind of wax and dirty electrical contacts. ...
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257 views

Auxiliary contacts on contactor to power solenoid valve

I'm just trying to introduce cold water in to industrial shredder. Connected cold water supply to machine. That's not good because when I forget to turn off water it will overflow. I have not seen ...
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Why are contactor coils connected to two different safety relay outputs?

When looking through a manual for a safety relay, I began to wonder why the coils of the load contactors (K3 and K4 on pages 14-15) are always connected to two different NO contacts of the safety ...
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Are three-phase contactors rated per pole or in total?

Are three-phase contactors rated per pole or in total? For example, have a look at this datasheet for a random three-phase contactor: datasheet In the datasheet it says that for AC-3 loads (1) the ...
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Switching a power contactor from an arduino / raspberry

I'd like to switch a power contactor (such as this one : https://www.legrand.fr/pro/catalogue/31925-bipolaires-250-v/contacteur-de-puissance-cx3-bobine-230v-sans-commande-manuelle-2p-250v-25a-contact-...
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CC12 Contactor is Confusing

I am attempting to use this relay, the CC12, to turn the 120VAC power to a motor/motor controller on and off using a 24VDC signal (These voltages are specified in the datasheet.), and I've gotten ...
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746 views

IGBT contactor design

I found this circuit in an older post. I was thinking about using this in place of a contactor to break under load. The load would be at 500V 300A DC. There would be overcurrent protection in line ...
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Controlling 2-pole contactor using Arduino

I am working with Packard C230C contactor to develop own EVSE. For a simple start i just want to toggle contactor using Arduino. OpenEVSE is already doing it. Just want to know how do they do it and ...