Picking some brains

[CallumWK]

Dear all, I have this gate motor. Foresee F500

 

https://www.aliexpress.com/item/1005005898394999.html?

 

Which has this limiter switch

 

https://www.aliexpress.com/item/1005002630161335.html?

 

Since this is a mechanical switch with a spring, it is always problematic. I have replaced the switch once already, but it lasts 1 - 2 years before it wears and stops working properly.

 

So I was thinking about replacing it with a magnetic switch

 

https://th.aliexpress.com/item/32793626989.html?

 

The principle of functioning is the same, the only problem I see is that the original switch works on 220V, while the magnetic one is 12V.

 

Is there a way with a step-down transformer or contactor to use it on my motor?

 

I know, the ideal solution would be to source a 220V version of the magnetic switch, but so far couldn't find one.

 

Your help is appreciated.

[CallumWK]

Nobody has any knowledge about this, or can point me to a 220V version of the magnetic switch.

 

If more info is needed, like a picture of the PCB of my motor, let me know.

[bluejets]

19 hours ago, CallumWK said:

Dear all, I have this gate motor. Foresee F500

The problem when linking to Aliexpress is it rarely shows the actual product you have.

Instead it opens the product page on the first in a line of products available.

 

However, if we are to assume you have a 220v AC motor (very similar to what I have here) then any external limit switch could have been anything really ranging from an enclosed 220v AC rated switch to a DC sensor low voltage limit.

 

Difference would be in how it interfaces with your original motor wiring.

 

One could use a 12V DC magnetic sensor which I imagine your "replacement" would appear to be (no actual specs supplied so who knows what is inside the grey box).

One feedback shown on the Aliexpress site (first really) says the buyer could not get any circuit on a multimeter and therefore decided the switch was kaput. 

However this is exactly the measurements one would expect from an open collector low voltage sensor.

 

If indeed low voltage as I suspect, it would be quite easy to interface from the magnetic switch output(possibly open collector) through a low voltage relay to your existing motor circuit.

There is one other aspect you have not mentioned. 

Normally one would expect to see 2 limit switches on the gate, one for open and one for closed limit.

 

Edit: On further inspection of (see more detail) on the web site, it appears your existing mechanical limit could be a 2 way device therefor some more thought needed for any "magnetic sensor" replacement.

The old system switch has 3 cables which one would expect to see in a 2 way switch of this nature....... so say gate closed for example the (common) white and blue may be open circuited as a limit and same for possibly (common) white and black for the other open direction detect.....these are only assumptions as I have no circuit diagram to make a definite conclusion.

 

Further down the Aliexpress page there is a reference video to replacing your original switch which is no more than two interconnected micro switches.

I don't know which part of your switch fails but assuming the microswitches, they can be obtained almost anywhere for maybe $2 a piece.

Again though, no way of knowing if it is 220v AC or low voltage BUT ...... as the switches are contained within the gate motor casing one could assume them to be 220V AC.

https://th.aliexpress.com/item/1005002630161335.html

 

Without further info on the new switch/switches and connections in a circuit diagram on the old switch/switches it is difficult to be more precise in any answer for a conversion.

[CallumWK]

30 minutes ago, bluejets said:

The problem when linking to Aliexpress is it rarely shows the actual product you have.

Instead it opens the product page on the first in a line of products available.

 

However, if we are to assume you have a 220v AC motor (very similar to what I have here) then any external limit switch could have been anything really ranging from an enclosed 220v AC rated switch to a DC sensor low voltage limit.

 

Difference would be in how it interfaces with your original motor wiring.

 

One could use a 12V DC magnetic sensor which I imagine your "replacement" would appear to be (no actual specs supplied so who knows what is inside the grey box).

If indeed low voltage as I suspect, it would be quite easy to interface from the magnetic switch output(possibly open collector) through a low voltage relay to your existing motor circuit.

There is one other aspect you have not mentioned. 

Normally one would expect to see 2 limit switches on the gate, one for open and one for closed limit.

 

Without further info on the new switch/switches and connections in a circuit diagram on the old switch/switches it is difficult to be more precise in any answer.

 

Thanks for your reply, finally got it going. 🙂 

 

The gate motor is a Foresee F500, below is a link to the English manual.

 

https://www.aggdoors.com.au/wp-content/uploads/2016/01/F500.English.pdf

 

 

The mechanical switch has 3 wires and is 220V AC, as does the magnetic switch, which is 12V DC.

 

The magnetic switch is available in NO and NC, but on my PCB I also can change between both.

 

This is inside the mechanical switch

 

 

Unfortunately, no info on what is in the magnetic switch is available.

 

[Fruit Trader]

Ignore the maximum rating on the existing micro switch (D45X 250V AC), it has nothing to do with the limit switch voltage used by your gate control PCB.

 

The F-500 circuit board uses low voltage electronic inputs for the limit switch so you will be ok using the magnetic reed type switches rated at only 12V.

[CallumWK]

24 minutes ago, Fruit Trader said:

Ignore the maximum rating on the existing micro switch (D45X 250V AC), it has nothing to do with the limit switch voltage used by your gate control PCB.

 

The F-500 circuit board uses low voltage electronic inputs for the limit switch so you will be ok using the magnetic reed type switches rated at only 12V.

 

Partly correct.

 

I just measured, and when put meter on AC I measure ~8V, when put meter on DC I measure ~5V. I measure at the PCB contacts

 

So how I know if it is AC or DC, as I think that will matter. Not?

[CallumWK]

Since the contacts in the mechanical switch are rated AC, I assume it is low power AC voltage provided by the motor.

 

Will it harm, or make it not functional, if the switch I connect is DC. Or is there a way to convert the AC power to DC?

[scotty1286]

8 minutes ago, CallumWK said:

Since the contacts in the mechanical switch are rated AC, I assume it is low power AC voltage provided by the motor.

 

Will it harm, or make it not functional, if the switch I connect is DC. Or is there a way to convert the AC power to DC?

The ratings on these switches are just the maximum voltage the switch contacts can handle, therefore makes no difference if low voltage AC or DC

[Crossy]

2 hours ago, CallumWK said:

 

Partly correct.

 

I just measured, and when put meter on AC I measure ~8V, when put meter on DC I measure ~5V. I measure at the PCB contacts

 

So how I know if it is AC or DC, as I think that will matter. Not?

 

What happens if you measure a 9V battery with the meter set to "AC". Some (mainly cheap) meters will measure "something" if set incorrectly, I suspect your 5V DC is actually what you have.

[Crossy]

6 minutes ago, scotty1286 said:

The ratings on these switches are just the maximum voltage the switch contacts can handle, therefore makes no difference if low voltage AC or DC

 

Unless it's a hall-effect switch, in which case AC will kill it.

[Crossy]

To be honest with the level of knowledge they're showing, by far the best course of action for our OP would be to continue his replacement of like for like.

 

 

[scotty1286]

1 minute ago, Crossy said:

 

Unless it's a hall-effect switch, in which case AC will kill it.

Agreed, NEMUR type cannot be used for AC unless specially designed, but the 2 types the OP mentioned are 'dumb' mechanical or magnetic type 

[CallumWK]

1 minute ago, Crossy said:

 

Unless it's a hall-effect switch, in which case AC will kill it.

 

Yes I was just reading up on that, and some websites say DC switch on AC is fine, but not vice versa, while others say need use rectifier.

 

So I guess that is what is needed when it's hall-effect switch. Correct?

 

next question, what is a rectifier and where to get it

[scotty1286]

3 minutes ago, CallumWK said:

 

Yes I was just reading up on that, and some websites say DC switch on AC is fine, but not vice versa, while others say need use rectifier.

 

So I guess that is what is needed when it's hall-effect switch. Correct?

 

next question, what is a rectifier and where to get it

Seriously, just keep changing like for like as previously suggested, maybe try to source higher quality standard microswitches to get longer out it

[Crossy]

@CallumWK these switches are sooo cheap, particularly if you just buy the actual switch element itself, that it really isn't worth your time messing about.

 

 

[CallumWK]

Thanks for the replies.

 

Like you said, I will order (think it's 800 include shipping) and see if it works.

 

if you should have a source for a higher quality one, please post a link.

 

Regards

[Fruit Trader]

3 hours ago, CallumWK said:

 

Partly correct.

 

I just measured, and when put meter on AC I measure ~8V, when put meter on DC I measure ~5V. I measure at the PCB contacts

 

So how I know if it is AC or DC, as I think that will matter. Not?

 

The limit switch inputs are pulled up to the positive rail, limit switch contacts pull them down to ground.

 

Set meter to DC if you want to read the voltage on these terminals.

 

 

As already mentioned, replace with same they are cheap enough to keep stock. If its only the micro switch that goes faulty they will be even cheaper.

[CallumWK]

Guess something got lost in translation.

 

With like for like, you mean replace with the original one?

 

The issue are not the micro switches but the spring.

 

After one or two years the spring wears, so when gate is open and want to close, the spring swings, so it moves only for 30 cm, then it stops, because the "closed" contact get hit by the swing

 

Tightening the spring doesn't work, because then it doesn't move anymore

[Crossy]

2 hours ago, CallumWK said:

The issue are not the micro switches but the spring.

 

Could you make alternative mechanical arrangements but still using micro-switches?

 

[VocalNeal]

Unless I misunderstand you will need an interposing relay to switch the 220V. Then you will need a 12v supply To power the relay. You might get away with using the 18v for the photocell. But...

 

❔Buy some mechanical ones and change whenever.

[CallumWK]

49 minutes ago, Crossy said:

 

Could you make alternative mechanical arrangements but still using micro-switches?

 

 

Can you explain what arrangements you have in mind?

 

The problem is this. The axle and the piece that holds the spring are both in plastic, so pretty soon the axle wears, and then the piece that holds the spring comes loose, making it swing when it slides off the limiter plate when closing the gate, and thereby touching the switch that tells the motor that the gate is at the closing end.

 

Such a switch is over 1000 baht including shipping, so not exactly cheap

 

[Fruit Trader]

2 hours ago, CallumWK said:

The problem is this. The axle and the piece that holds the spring are both in plastic, so pretty soon the axle wears, and then the piece that holds the spring comes loose, making it swing when it slides off the limiter plate when closing the gate, and thereby touching the switch that tells the motor that the gate is at the closing end.

 

Such a switch is over 1000 baht including shipping, so not exactly cheap

 

A good quality whisker type limit switch could be a solution but the problem is you have limited space inside of the case to fit a more robust bulky switch bearing in mind the ideal switch location is inside of the enclosure away from rain.

 

Below is example of a gate motor with magnetic limit switch. The switch sits close to the cover and the magnets mounted on the drive rail are strong enough to activate the magnetic reed switches.

If you are capable and have the tools to make adjustments to the switch mount give the magnetic solution a try.

 

[bluejets]

7 hours ago, Fruit Trader said:

magnetic reed switches

Reed switches will never have the current carrying capability of what may be required by the existing circuitry.

Reed switches to be used in such an instance would have interface buffers.

As I said originally and others have echoed, get the moths out of the wallet and buy a new "original" limit assy.

[Fruit Trader]

 

Edit

[Fruit Trader]

2 hours ago, bluejets said:

Reed switches will never have the current carrying capability of what may be required by the existing circuitry.

Reed switches to be used in such an instance would have interface buffers.

As I said originally and others have echoed, get the moths out of the wallet and buy a new "original" limit assy.

 

The F-500 circuit board limit switch inputs will be passing a few milliamps when pulled down. Reed switches are more than capable for this application. I know this because the brother in law has sketches of the Chinese F-500 PCB diagram on file.

 

 

F-500 low current low voltage inputs :-

 

 

[CallumWK]

12 hours ago, Fruit Trader said:

If you are capable and have the tools to make adjustments to the switch mount give the magnetic solution a try.

 

I'm known to have 2 left hands, but how about glueing the switch to the outside of the motor housing. Would it be water resistant?

[OneMoreFarang]

You need a relay:

 

Here are the details:

https://electronics.stackexchange.com/questions/317227/how-to-command-a-220v-device-through-a-12v-output

 

 

[Fruit Trader]

1 hour ago, OneMoreFarang said:

You need a relay:

 

Here are the details:

https://electronics.stackexchange.com/questions/317227/how-to-command-a-220v-device-through-a-12v-output

 

 

 

Where is the 220V that requires commanding via a 12V relay? This is an electronically controlled gate motor with logic level inputs for reading gate position.

 

The OP is looking for more reliable limit switches for the low voltage inputs. He has suggested  magnetic switches which is not a bad idea as many controllers now use this method. 

[OneMoreFarang]

22 minutes ago, Fruit Trader said:

 

Where is the 220V that requires commanding via a 12V relay? This is an electronically controlled gate motor with logic level inputs for reading gate position.

 

The OP is looking for more reliable limit switches for the low voltage inputs. He has suggested  magnetic switches which is not a bad idea as many controllers now use this method. 

Yes, and he can use the magnetic switches with 12V to trigger the relay. And the relay switches the 220V for the motor. It's not really that difficult. 

[bluejets]

1 hour ago, OneMoreFarang said:

Yes, and he can use the magnetic switches with 12V to trigger the relay. And the relay switches the 220V for the motor. It's not really that difficult. 

The complexity arises when one has to consider two limits and how they may/may not interact.

This combined with "what will be the fail safe mode" so one relay is not constantly required to be powered when gate is in open or closed position.

Not being picky here, I simply know it's not as easy as one first assumes.

 

Any that think it is, please feel free to post your circuit diagrams here for perusal and objective criticism.

 

As before, simplest is just buy a new switch unit, it's not all that unreliable.