Relay Control based on Generator RPM

Hey guys,

I am building a project where I want to turn on/off the relay based on the RPM threshold of the generator.

The circuit diagram is as follows:

Wind generator -> Charge Controller -> Relay -> Battery

Basically, I wanted to connect the charge controller to the battery only when the generator reaches a certain RPM and disconnect the charge controller from the battery when the RPM drops below the preset RPM.

The Max current and voltage the relay has to handle is 60VDC and 60ADC. CAn someone recommend a relay that can be used for this purpose as I was not able to find such relay. Also, is this a good approach to do this task?

Thank you

There are specialist contactors or semi conductor switches -current and DC voltage make it hard - look at wind/solar power sites you might get something there .
Google the spec you have.

Are you sure you will be charging at 60A ? you will need to control current voltage by some means to prevent overcharging .

The circuit diagram is as follows:
Wind generator -> Charge Controller -> Relay -> Battery

That is not a circuit diagram!

However...
I would expect a relay with the specification you gave to be an expensive beast. Try searching for contactor. If your aim is to only draw power from the wind turbine when it is going fast enough to be useful I would expect that to be taken care of electronically in the charge controller. I would expect the charge controller to only draw power from the turbine when there is power available to be drawn, so in answer to the question 'is this a good approach', no, I don't think so. Design / buy a charge controller that is appropriate to the task.

Are You completely sure that the generator and charge controller will manage being switched like that? It would be sad if equipment would be damaged, burn or worse.

A decent charge controller will already have the capability. It’s part of being a charge controller.

I hope you have a load for the generator when the charge controller is not connected.

Paul

hammy:
There are specialist contactors or semi conductor switches -current and DC voltage make it hard - look at wind/solar power sites you might get something there .
Google the spec you have.

Are you sure you will be charging at 60A ? you will need to control current voltage by some means to prevent overcharging .

Thank you for the response, using a contactor is a good idea because of higher voltage and current. Can a 5V relay be sufficient to switch on/off the contactor or does that depend on the manufacturer?

I am looking at this one: https://www.automationdirect.com/adc/overview/catalog/motor_controls/iec_contactors_-z-starters-z-overloads/gh15_series_contactors-z-starters-z-overloads/60mm_contactors(40_to_63_amps)_-z-_overloads

Also, 60A is just me being conservative

PerryBebbington:
That is not a circuit diagram!

However...
I would expect a relay with the specification you gave to be an expensive beast. Try searching for contactor. If your aim is to only draw power from the wind turbine when it is going fast enough to be useful I would expect that to be taken care of electronically in the charge controller. I would expect the charge controller to only draw power from the turbine when there is power available to be drawn, so in answer to the question 'is this a good approach', no, I don't think so. Design / buy a charge controller that is appropriate to the task.

Yep, sorry for calling it a diagram! I am looking for a contactor, please check previous comment, Any insights would be helpful

Railroader:
Are You completely sure that the generator and charge controller will manage being switched like that? It would be sad if equipment would be damaged, burn or worse.

To be honest, I am not sure, I assume turning on/off the breaker in a sub panel while there is power in it. What do you think? Any recommendation around this? Thanks

The contactors you link to are AC rated.

It may be they do have some kind of DC rating but I would imagine it would be vastly different from what is shown.

I assume turning on/off the breaker in a sub panel while there is power in it.

A good way to get your hand or your head blown off in the ensuing explosion.

A generator loosing its load, the battory, will create a "load dump", a high voltage, probably sparking and that will kill equipment not especially proteted against that. It's a well known fact among car designers etc.

https://www.ametekswitch.com/products/dc-contactors-list/model-ja-46-100-150-amp-dc-contactor

bluejets:
The contactors you link to are AC rated.

It may be they do have some kind of DC rating but I would imagine it would be vastly different from what is shown.

I assume turning on/off the breaker in a sub panel while there is power in it.

A good way to get your hand or your head blown off in the ensuing explosion.

Got it, so is connecting the charge controller to the battery when the generator is spinning is not a safe way to do?

Railroader:
A generator loosing its load, the battory, will create a "load dump", a high voltage, probably sparking and that will kill equipment not especially proteted against that. It's a well known fact among car designers etc.

How do I protect the equipment? Do I need to have a breaker between the contractor and the battery?
What are the chances this set-up will pass or fail?

The operation is: When the generator reaches 100 RPM (for example) I want the charge controller to connect to the battery and when it reaches below 100 RPM it will disconnect. My plan is to have a contractor between the charge controller controlled by a relay and arduino to perform this operation.

I assume there is no way to controll the wings of the windturbine, setting them to idle, not catching any wind. Spinning the turbine at low RPMs for large amounts of time is liklely not good either, causing ware to bearings, commutators etc.

As I am unaware of many facts in Your construction, I ask: Why do You want to disconnect the generator like this? It might no be that very easy.
I once worked for a car manufactoring company but I have forgotten too many details. A filter is needed that firstly limits the current and then grounds the overvoltage, possibly using a strong zener diode, or circuitry.

A second thought. Is there any way You can tell the battory charger to stop draw current from the generator? That would be a good way to go.

usernameous:
The operation is: When the generator reaches 100 RPM (for example) I want the charge controller to connect to the battery and when it reaches below 100 RPM it will disconnect. My plan is to have a contractor between the charge controller controlled by a relay and arduino to perform this operation.

Why , what is so important about connecting and disconneting at a certain RPM?
How will you measure the turbine RPM?
Is your charge controller designed for a wind turbine?
What make/model is your turbine, is it AC alternator or brushed DC type?

A PV controller is not suitable.

When a turbine is disconnected from batteries because they are charged OR because it is a situation that demands disconnection, the turbine is switched over to a "Dummy Load" to absorb the energy from the turbine.

Running a turbine unloaded is not good for the machinery and can be plain DANGEROUS.
Most turbines have non electrical methods to stop over speed, from applying a mechanical break to turning the turbine away from the wind.

Thanks.. Tom... :slight_smile:

usernameous:
Got it, so is connecting the charge controller to the battery when the generator is spinning is not a safe way to do?

A contactor designed for the job would be fine.
Manually operating a circuit breaker or isolator is not.