[BESTCO]

I am trying to set up a Tree JourneyMan 250 using acramatic 2100. I'm getting an error on startup (Alarm 90-4) saying that "Coolant motor overload protection has tripped. Remedy: Reset motor overload, check motor current." I have tried to replace the fuse in the back, but that has proved to be unsuccessful. I'm guessing it may be a voltage hookup thing, or something is wrong with the coolant circuit. I am wondering if anybody else has had a similar problem and how they fixed it.

And a question: does the coolant pump have to be hooked up and running in order for the mill to work?

Any input would be greatly appreciated!

[underthetire]

It's not a fuse. It's a thermal overload on the coolant pump contactor. Should have a reset on it. No, the machine doesn't need the coolant pump hooked up, as long as the wire is not dangerous. Like mom said, wrap it up.

[BESTCO]

Thank you for you help. I have found a red button (on the thermal protective relay) that looks like it should be the reset, but I am unable to set it back (stays popped out). I taped it down to see if it was just unable to be popped back in, but when I booted the system up, it still had the error message. Tomorrow, I'll hopefully be able to figure out if the thermal protective relay needs to be replaced? This mill had been working just fine a couple weeks ago from the guys we bought it from which makes it all the more frustrating. Thanks again for your response and help.

[Al_The_Man]

With the power off you can also check resistance for 0 ohms from the top of the O/L terminal to the corresponding bottom terminal. Some O/L's are mounted separate to the contactor, others are integral, but same function.
With the contactor non-activated the reset should stay in, and only possibly pop back out when the contactor is picked up, if overload exists.
Al.

[BESTCO]

I just did what you suggested (with the power off), and am getting a reading of 2 ohms between corresponding terminals (it is an integral O/L). What does this mean? and what would you suggest next?

[Al_The_Man]

0v to 2 ohms looks right.
O/L = over load.
(Alarm 90-4) "Coolant motor overload protection has tripped.

Somewhere it has to get this information and is usually the N.O/N.C. monitoring contacts on the O/L.
These are low voltage inputs into the controller?
You could also see if the the one(s) that are wired are registering open or closed, or opposite to what they are labeled (tripped state).
Al.

[BESTCO]

N.O./N.C. contacts? Where are these located. I'm sorry I'm new to all of this and don't know the technical terms/abbreviations a whole lot.

I attached some photos of the controller I'm working on. The red switch on the right is what I'm assuming to be the trip.

Attachment 186332Attachment 186334

[Al_The_Man]

I am not that familiar with Schrack products, but it looks like the unit with the Schrack label on is the O/L relay?
If so the wires connected to it may be the N.O. (normally open) contacts that close for the alarm when the O/L trips?
You really need a schematic to identify the wires by wire No.
Often the N.C. are wired to the coil as an interlock and the N.O. to the controller for an alarm?
Al.

[BESTCO]

Somehow the error went away when I disconnected and reconnected the wires on the contacts for the trip and changed the input and output voltages (even though it shouldn't matter because it's A.C.) but got past that first error. Thanks for your help. Just tripped another alarm by going too far on the z-axis, but am getting the hang of it now. Thanks again.

[BESTCO]

Turned the machine back on today, and the coolant error message popped up again. Same one. Struggling now with ideas on what to do. What might anybody suggest I try?

[Al_The_Man]

Is the pump actually off and is the contactor picked up?
Al.

[BESTCO]

Yes. There is no current flowing through the pump. And there is two ohm resistance across the overload protective relay.

[Al_The_Man]

Do you have the machine schematics?
Al.

[BESTCO]

Yes. Both the mechanical and electrical. From them, I've been able to locate almost everything.

[Al_The_Man]

I assume the contactor is not picked up?
I would see physically and from the schematics if the O/L monitor contacts go to the control and if they are in the state they should be in for normal operation?
IOW, if there is a connection from the O/L to the controller, say the N.O., is it actually open?
If not is the state of the input that it goes to have an indication of any kind such as a LED status light.
Most of this can be traced on the schematic.
Are the control inputs labeled? e.g. Pump O/L etc?
Al.

[BESTCO]

Yes. All the wires and connections are labeled. I've been trying to trace back from the pump the wires and O/L monitors, but there is no default information on the schematics on where wires should be connected etc. So it has been trial and error for much of the process.

I talked with somebody who knows a little bit about Tree and he suggested that I disconnect the power side of the O/L monitor to see if that got the error to disappear, and it didn't. So his suggestion is that the O/L is either debunk, or the motor has been shorted out.