Wiring Octal 11-pin Latching Relay

The lubrication systems that I've seen are monitored by flow and/or pressure switches; they only utilize a level (float) switch to prevent them from running empty and to signal your equipment.

There are other systems which monitor the stroke of a pneumatic plunger that pushes oil thru the metering valves on your machine.

What you describe, sounds to me like one way of controlling the replenishment of a reservoir, not a lubrication system.

Before you can get any advise about the schematics, you have to describe very carefully and step by step, one full lubrication cycle of your system.

Regards

P.D. Latching relays retain their last state regardless of power cycles, please make sure that's what you want.

This is a one-off, gravity fed system. You're right in that this is really a reservoir filling system.

2 reed switches in the remote reservoir will cycle the clean reservoir pump, while 2 in the dirty reservoir will control the dirty reservoir pump. The switch in the clean reservoir will kill the machine if it runs too low.

So:

Pump A - will turn on when remote res. "low level" float contacts. Then will turn off when remote res. "high level" float contacts. This is why I'm using latching relays.

Pump B - will turn on when dirty res. "high level" float contacts. Then will turn off when dirty res. "low level" float contacts.

Hello Johnny, it is a good description; got to leave now, let's take a look at it tomorrow.

Regards

What's the function of the low level reed switch in the clean reservoir?

Also, please give the manufacturer & part no. of the latching relays. Same for contactors & overloads and reed switches would also be handy.

Can't just throw something like this together if you expect it to work reliably - got to check the details.

The low level switch in the clean reservoir will be integrated into the machine control, not this circuit. If the clean reservoir runs dry it'll turn the machine off.

I realized the auxiliary contact is unnecessary, as I'm not using two switches like the diagram is.

My setup consists of :
FLT-243 Reed switches - http://www.chicagosensor.com/Horizontal_Mount_Stainless_Steel_Float_Switches.html

Contactor - http://www.automationdirect.com/adc/Shopping/Catalog/Motor_Controls/Fuji_Contactors_-z-_Overloads/9_to_25_Amp/SC-E03-110VAC

Thermal overload - http://www.automationdirect.com/adc/Shopping/Catalog/Motor_Controls/Fuji_Contactors_-z-_Overloads/9_to_25_Amp/TK-E02-900

Latching relays - http://www.automationdirect.com/adc/Shopping/Catalog/Relays_-z-_Timers/Electro-Mechanical_Relays/Latching_Relays,_Octal,_16A_(755_Series)/755-2C-120A

Control philosophy:

"When the remote reservoir high level switch operates, pump A turns off. When the remote reservoir low level switch operates, pump A turns on. When the dirty reservoir high switch operates, pump B turns on. When the dirty reservoir low switch operates, pump B turns off. When the clean reservoir low switch operates, both pump A and pump B turn off until the low switch changes state a second time."

Is this correct?

What happens when there is a high level in clean reservoir? Does it overflow? Where does the make-up fluid come from and how does it get into the system?

Thank you! This is what I was looking for.

I've already ordered the aux contacts (http://www.automationdirect.com/adc/Shopping/Catalog/Motor_Controls/Fuji_Contactors_-z-_Overloads/Auxiliary_Contacts/SZ-AS1T) and they should be delivered today.

Can I run it for a week or so without the surge suppressor?

So can I just do this?

What is the the pump you're referring to? A or B? anyway, doesn't matter because this circuit won't work properly.

If it is for pump A, then it will run 'till it fills the remote reservoir, then will keep cycling on and off more often than necessary and will keep the reservoir very close to the full level.

If it is for pump B, then it will pump whenever the level is between high and low, but will latch thru the aux. contact and will keep on running even after your tank is dry !.

Regards

Try this, it should work.

First, an apology - the coil inrush of these contactors is rated at 90-95VA, and the float switches are rated at 50W (although they're spec'ed at up to 220Vac, 1.5A). So for reliable operation over time, an additional relay will be needed (per pump).

However, the circuit Jonny's drawn will work.

The switches aren't drawn correctly, but the "NO" and "NC" legends are correct for pump A. When the level drops to the NO low level switch (AKA START), the contactor pulls in latches via the aux contacts and the NC high level switch (AKA STOP).

When the level reaches the high level switch, the (STOP) contacts open and the contactor drops out. Note that the START contacts are now open, and won't re-close until the level drops back to the low level switch, by which time the STOP contacts will have closed again.

Jonny - it will work as you've drawn it, but (especially without coil suppression) the float switch contacts may weld - which could mean you have a nasty overflow. I'll try to post a full circuit tomorrow.

Apologies again to each - especially if I've caused you additional expense, Jonny.

Hey, no problem John , you just might want to rethink the operation of the low level switch for pump A, if you use a N.O. it means it wil be closed all the way from low level to high level.

Regards

And I'm sorry, yes the low level switch would be NC. When I put NO on the diagram, I was referring to it when the fluid level was between both floats, ie the "normal" condition. Not "normal" as an electrical engineer or electrician would be thinking.

This is how I had the switches mounted initially.

But this is how you both are saying I should do them, correct?

If this is right, I'm afraid I may not have left enough room between the reservoir lid and the high switch to allow it to open...

The orientation of the switches makes no sense without some idea of the switch contacts available from them.

Wouldn't it be easier to consult someone locally who can sort all this out?

If the floater pointing upwards means N.C., then yes, but only for pump A (see post #23).

If space is a concern, there are a whole lot of level sensing devices in the industry, you might want to visit Omega homepage, depending on the thikness and density of your tank walls, you could even use capacitive adjustable sensors to detect the oil level thru the walls !.

Regards

Yep. Latching relays not needed. GA

It's been awhile since electronics class, but isn't this basically how I should set it up?

PLEASE DISREGARD THIS DIAGRAM...

Roger that.

I'm curious why you want to use latching relays. That makes the circuit a lot more complex and presents challenges as to how you want it to react to power failures etc. The usualy practice it to have a regular relay and use a "seal in" contact of the relay itself to hold it in until the circuit drops out for other reasons, including a power loss. That way the system does not automatically retain it's state when power is restored, it starts over again. Think that one through a little more if you don't know exactly why you wanted a latching relay.

The latching relays are being used because I want the low level switch to turn the pump on when it closes, but don't wan't the pump to turn off when the switch opens. The pump will turn off when the high level switch closes and not turn on again when it opens.

Wire the lower reed switch where the start button was, and the upper switch where the stop button was. Use the motor starter/relay auxiliary contact as shown; omit the latching relays.

An octal base relay has eight pins.

They come in 8 and 11 pin varieties.

See: http://www.automationdirect.com/adc/Shopping/Catalog/Relays_-z-_Timers/Electro-Mechanical_Relays/Latching_Relays,_Octal,_16A_(755_Series)/755-2C-120A

An 11-pin relay won't fit an octal base. One needs an 11-pin base for an 11-pin relay.

We're getting off track. I have an "11 pin octal relay" (as specified by automation direct) and appropriate base. This is not my problem...

Hurrah.

Hello Johny;

Everybody's right, you don't need any latching relays, you need "normal" octal relays and use one of their contactas as a retention, I drawn this for you, as per the power part of the circuit, wire the loads as described in the schematic that you posted: "full voltage..." here you go:

HELP !!!! I don't know what the heck is wrong with my computer this mornig !

Can I attach files to a post? or how can I send a picture by private message to Johnny?

I can't believe this s**t ! Now I was able to post a large pic !!!

Will try again with my hand drawn diagram...

First switch at the top is Clean Reservoir Low, N.O.

In the middle line, to the left you have the Remote reservoir High N.C. switch; to the right is Remote Reservoir Low N.C.

Bottom line, to the left: Dirty Reservoir Low N.O. To the right Dirty Reservoir High N.O.

Get rid of your latching relays and get a couple octal sockets and relays (8 pins).

Regards

Extra relays (latching or not) not needed. See #17 (and #18).

I know you can use auxiliary contact blocks in the same contactor, but some times, large coils are too heavy for sensors or small switches, thats why we see control relays energizing them.

In this application the OP might want to consider the contac rating of his level switches and determine whether he needs CR relays or not.

Regards

Sorry

It can not be both Octal and 11 pin.

Octal connections for round 8pin Electronic-Vales/tubes was adopted for other electrical parts like relays. In octal normally we find 2pCO contacts with 2 pins for the coil.

For 3PCO 3 extra connections are required and a new socket 11pin in the size of Octal socket was added..

Regards

I disagree. A single dual pole relay where one set of contacts is used for latching action is needed for pump-up action.

Pump-up is used to turn a pump on at a low level switch point, keep the pump running until the high level is reached. At the high level switch point, the pump turns off and stays off until the level drops to low level switch point.

Pump-up action requires a latching action to keep the pump on after the low point switch trips as the level rises above it.

The sketch below shows pump-up control with 2 level switches and a double pole relay. The level switch contacts are closed below the trip setpoint and open when the level rises above the switch trip point. The relay contacts need to be capable of handling the pump load.

This action is called "pump up" and it requires latching action to keep the pump on when the low level trips as the level rises above its trip point.

At 'empty' (below low level), both LS1 and LS2 are 'made' or closed, energizing the relay coil K so the pump turns on. At the same time, the latching contact K is made. As the level rises above the lower level switch point, LS 1 opens, but the motor continues to run because the latching contact K holds the relay coil in.

As the level rises, eventually LS2 trips and opens, dropping out power to the relay coil, stopping the pump motor and opening the latching contact K. At that moment LS1 is open, LS2 is open and the latching contact K is open.

The level doesn't have to fall too far (deadband or hysteresis) before LS2 makes, but the relay's coil stays unenergized until the level falls below LS1, at which time LS1 makes and energizes the relay coil and the cycle repeats.

If you just could decipher my horrible drawing in post #23 you'd see we are talking exactly about the same circuit (for pump A), the other one (pump B) prevents overflows, so it basically works in the oposite way.

Regards