Project Help

[wreck-it-steve]

Hi,

I am working on a little project and need some help. I need an alarm to sound when a few possible things happen.

1. Circuit breaker one trips
2. Circuit breaker two trips
3. Float switch is active

I have got aux contacts fitted to each breaker. How would i wire this so that is any of the three happen the alarm will sound and a seperate led will come on for each one?

Thanks

 

[RF Lighting]

You need wire each set of contacts to a DPDT relay.

Each relay has two sets of isolated switches.

All six switch commons connected to +9V

Relay one N/O switch contact one to LED one
Relay two N/O switch contact one to LED two
Relay three N/O switch contact one to LED two

connect all the N/O switched outputs from all three relays together to the buzzer

 

[mattylad]

How about have each of the Aux relays N/C contact pair supply +v to another low voltage (I.E 12v) relays coil+ via a diode, use 1 set of contact for the led & buzzer each via a diode (That way the individual leds can be on independently and the buzzer will be on for any of them).

Use the other set of contacts on the low voltage relay to also supply +v to the coil+ (via a diode) so that it latches the relay on.

While the circuit breakers do not need to be latching, the float switch may so I'd suggest using some form of latching the relay as above.

Don't forget resistors for each of the leds and a reset switch to knock the +v off to it all, use whatever voltage relays you can find a small psu for, heck might as well make one of those too.

If thats hard to follow I can draw it out and t'others can pull it to bits for not meeting some reg or other

 

[plugwash]

No need for relays, a few diodes and resistors (for the LEDs) is all you need. Plus a power source of course.

 

[bernardgreen]

Depending on where the supply for the alarm comes from you may need to consider an alarm for when that power source can no longer operate the buzzer. As with most alarms they are seldom used to indicate an alarm so loss of power to the alarm indicators can easily go un-noticed.

 

[mattylad]

This needs more specifications or we will just assume lots.

Things like..

Does the alarm need to be low voltage? (I.E. 12v etc)
Do the alarms need to be latching even if the float goes inactive?
Does it need to be battery backed?
What voltage sounder are you thinking of?
Have you got any bits for this yet? if so what?
Where will the sounder and leds be situated? in the CU or externally?

Does the sounder need to be continually sounding?
Do you want to be able to silence the alarm without resetting the mcb's?

What colour leds?
What sounder type? plain buzzer or some other sort of sound?

The list goes on & we could make up circuits till the cows come home but might not get it right for the situation until we know more.

 

[wreck-it-steve]

This needs more specifications or we will just assume lots.

Things like..

Does the alarm need to be low voltage? (I.E. 12v etc)
Do the alarms need to be latching even if the float goes inactive?
Does it need to be battery backed?
What voltage sounder are you thinking of?
Have you got any bits for this yet? if so what?
Where will the sounder and leds be situated? in the CU or externally?

Does the sounder need to be continually sounding?
Do you want to be able to silence the alarm without resetting the mcb's?

What colour leds?
What sounder type? plain buzzer or some other sort of sound?

The list goes on & we could make up circuits till the cows come home but might not get it right for the situation until we know more.

Hi,

Supply voltage to all the control circuits will be 24v I need the alarm and LED's to be on all the time upon alarm and then be able to silence the sounder before reset of breakers.

This will all be contained within a small control panel.

Thanks

 

[ericmark]

Think DC instead of AC and it becomes easy.
The aux contact supplies the light and through a diode matrix the lights supply the alarm.
A three phase rectifier is likely the easy way to package and connect may look better than diodes on their own.

 

[mattylad]

Can you explain a little more about the float switch to me?
Does this come on and latch or go off when the water level changes?

Has this also got an aux relay wired to it?

 

[wreck-it-steve]

Can you explain a little more about the float switch to me?
Does this come on and latch or go off when the water level changes?

Has this also got an aux relay wired to it?

The purpose of the float switch is to tell us of high water level. It will go off as the water level goes down. every part of this needs to be able to silence the alarm.

 

[333rocky333]

I have got aux contacts fitted to each breaker.

Intriqued what make mcbs are they

 

[ericmark]

To silence the alarm means some form of relay. Be it a mechanical or JK flip flop is immaterial at this stage as we don't know enough about what you are doing.

In the past I have been presented with this type of problem but it has always had some other items which needed switching on or off at the same time.

As a rule of thumb we considered three or more timers meant it was cheaper to use a PLC and as a result nearly every time this sort of problem has arisen we have been using PLC control so that was also used to control warning lamps and sounders.

So do tell us more about what you are doing. Using PIC's is cheaper than PLC control but I will admit I was never any good at programming PIC's.

However you may want to look at the Microchip web site and see if they fit the bill. Please note Microchip is a trade name.

 

[wreck-it-steve]

I have got aux contacts fitted to each breaker.

Intriqued what make mcbs are they

Merlin Gerin

 

[wreck-it-steve]

To silence the alarm means some form of relay. Be it a mechanical or JK flip flop is immaterial at this stage as we don't know enough about what you are doing.

In the past I have been presented with this type of problem but it has always had some other items which needed switching on or off at the same time.

As a rule of thumb we considered three or more timers meant it was cheaper to use a PLC and as a result nearly every time this sort of problem has arisen we have been using PLC control so that was also used to control warning lamps and sounders.

So do tell us more about what you are doing. Using PIC's is cheaper than PLC control but I will admit I was never any good at programming PIC's.

However you may want to look at the Microchip web site and see if they fit the bill. Please note Microchip is a trade name.

The whole aim of the project is to control two pumps. I need to know when each pumps breaker trips and when the water level is too high. I only want to use relays and contactors.

 

[mattylad]

What about this?

When any input causes its aux relay to switch it supply's 24v to its respective relay via the diode, the relay turns on and latches because 1 contact is used to also supply 24v via diode to the coil.
This in turn supplies both led and buzzer.
The diodes are to ensure that 1 circuit does not interfere with another.
The push button resets it all by removing the 24v and unlatching the relays.
Additional circuits coming on will also light their leds.

All relays are 24v DPCO, diodes something like 1N4001 up, LEDS whatever colour you want(Red), Resistors 2K 0.25w.
Push button switch needs to be able to maintain current for the buzzer +60ma.

You may wish to use a biased keyswitch instead of a push button.

3 way alarm

• mattylad
• 8 Jan 2012
• 1

E&OE