# Need Cutler Hammer Thermal Selection Advise



## Uglydog (Nov 28, 2014)

I'm working on the resurrection of another Boye & Emmes lathe (yes, I have two).
This one has a 3phase, 7 1/2 hp motor. The plate says it draw 21amps at 220v.
She came with a much newer Cutler Hammer NEMA#1 Starter. 
However, the Themals have been jumped, and I'd like to change that before I power up.
Based on my reading of the chart:

http://www.westernextralite.com/resources.asp?key=66

I want either a H1043 or a H1044.
Is it better to upsize or down size a Thermal?
I'm guessing the H1043 is the right choice. 

Gratitude to Russ Harman for the inspiration to do electrical correctly.

Suggestions anyone?
There are some critical semantics about temperatures on the link above and the implications for Thermal selection.
It doesn't make much sense to me.
Suggestions please...


Thank you,
Daryl
MN


----------



## JimDawson (Nov 28, 2014)

I think you'll be fine with the 1043s.  The thermal data is for locations where the motor is located remote from the starter and may have large ambient temperature differences, like the motor outside and the starter inside.  That won't be the case with your lathe. The starter and the motor will be in the same ambient conditions.


----------



## Cheeseking (Nov 28, 2014)

I would agree with going lower.   Nuisance trip is better than frying the motor.


----------



## Uglydog (Nov 29, 2014)

Thank you both for confirming my read of the CH chart and the 1043.
As well as the explanation of the temps.

Please note that my comment about Russ Harman was merely to recognize the many, many hours he spent off line coaching me about electrical on a different project.

I'm learning, slow... but forward.

Daryl
MN


----------



## rdhem2 (Dec 6, 2014)

The previous two gentlemen have given you the straight skinny UglyDawg.  Must figure too that you will seldom, if ever max out that big old horse.  That is a lot of power just for turning pen bodies!

By the way, you are very kind in your remarks.

Thank you, 

Russ

Was still trying to locate some heaters but have not been to the shop much the last couple weeks and trying to hold the number of emails down because of your other issue.  Still kicking around, please let me know if you still need the heaters and am still happy to assist if I can.
                  :thumbzup3:


----------



## Uglydog (Dec 7, 2014)

rdhem2 said:


> The previous two gentlemen have given you the straight skinny UglyDawg.  Must figure too that you will seldom, if ever max out that big old horse.  That is a lot of power just for turning pen bodies!
> 
> By the way, you are very kind in your remarks.
> 
> ...



I found 3 heaters on Ebay. I proceeded to install them and noticed one of the "posts" is missing.
I was surprised that I could find appropriate posts on Ebay as well.
Do the heaters and posts really just screw into place where they seem to fit.
Other than the "in" and "out" wires are there any other connections?


Daryl
MN


----------



## rdhem2 (Dec 8, 2014)

Mr. Dog;
Yes, all the parts you speak of are mechanical in nature.  The electricity flows from the Line to the contacts. Then from the contacts to the top heater screw, through the heater to the bottom heater screw out to the motor.

The post you speak of should have a ratchet wheel on the back that is restricted from movement by solder in the post.  The wheel is connected to a rod that goes into a tube where the solder is. This is calibrated to a certain range of current flow.  When the current gets too high the solder melts allowing the spring loaded ratchet wheel to turn.  This releases a set of contacts in the overload block which opens the circuit to the coil of the magnetic starter shutting the whole conglomeration down.  The weak spot of this system is that every time a heater trips it pukes out a small dab of solder, thus changing the calibration of the heater, most always to a lower trip level.  If you regularly load your motor to maximum under these conditions, it won't be long before it won't stay on line due to nuisance tripping.

Also, all CH heaters have two ranges, hence the two numbers in the chart.  Look close and you will see that the little metal tab with the heater number is shaped like an arrow.  Arrow tab down low range, tab up high range.  It all has to do with the mechanical spacing of the heater on the tube of the heater, really called a eutectic alloy heater.

Glad you ask now aren't you?         :talktogod:       Stay with it, you will master it, glad to help.


----------



## Uglydog (Dec 13, 2014)

Got the CH post! 
All the prior responses make sense based on what I'm seeing. Thank you!!

Pic included for those that might want to follow this thread but don't have a CH handy. 

However, there is a rod/tab that I can see, and you might be able to see, might but unlikely do to the shadow, in the upper right hand corner of the center thermal slot in the box. I

s the channel on the bottom side of the post (I'm holding it in the pic) supposed to capture the rod when I assemble? If so, how do I get the rod into position? It seems retracted into the body of the thingy.

I can't imagine how those little electrons are smart enough to know where to go. They must all carry little maps!


Thank you,
Daryl
MN





rdhem2 said:


> Mr. Dog;
> Yes, all the parts you speak of are mechanical in nature.  The electricity flows from the Line to the contacts. Then from the contacts to the top heater screw, through the heater to the bottom heater screw out to the motor.
> 
> The post you speak of should have a ratchet wheel on the back that is restricted from movement by solder in the post.  The wheel is connected to a rod that goes into a tube where the solder is. This is calibrated to a certain range of current flow.  When the current gets too high the solder melts allowing the spring loaded ratchet wheel to turn.  This releases a set of contacts in the overload block which opens the circuit to the coil of the magnetic starter shutting the whole conglomeration down.  The weak spot of this system is that every time a heater trips it pukes out a small dab of solder, thus changing the calibration of the heater, most always to a lower trip level.  If you regularly load your motor to maximum under these conditions, it won't be long before it won't stay on line due to nuisance tripping.
> ...


----------



## Chiptosser (Dec 13, 2014)

I have a question,  are you using a rotary phase converter?
With some equipment, you have to vary the heater values on the power feed legs, to compensate for no amperage on the wild leg.


----------



## Uglydog (Dec 13, 2014)

Yep, 20hp RPC. Need the size for my 10hp lathes.


Sent from my iPhone using Tapatalk


----------



## Chiptosser (Dec 13, 2014)

I don't have a heater chart in front of me, but on the two power legs, you will need a larger amp heater.  Your power is being taken from these two legs and shared so to speak, with the wild leg.  You have no amperage generated on the wild leg.  your cap's will be jumpered from one or both power legs to balance the voltage between legs. This is why these two will have a higher capacity, to keep them from triping, they are drawing more amperage.


----------



## UncleRuss (Dec 14, 2014)

Mr. Dog:
Lets back up a step or two for a minute to cover something we may have over looked.  Instead of trying to explain the whole picture lets do this:
Remove the heater from either T1 or T3.
Remove the two small screws holding the solder post.  When you pull it out you will hear and sense a snap.  This is the overload block tripping out just as it had tripped in normal use.  Look into the hole and you will see a horizontal piece of spring steel with a little dog leg bent on it.  This is what engages the ratchet wheel on the back of the solder post.  Now look in the hole for T2.  If the steel piece *is not *there the overload block was built to be a single phase unit.  If the hole for T2 looks the same as for T3 then just reassemble everything and when finished push the metal bar sticking out the front of the block to reset the block, thus closing the circuit through the overload block.
If the metal piece is not evident then the overload block is single phase and needs to be replaced to be effective for three phase use.
There seems to be some concern about the trip value of the overload block.  Lets look at it this way, it is intended for and only effective for long term overloads.  The UL standard for NEMA rated overloads is referred to as class 30.  Meaning that it should trip after a 30 second continuous overload condition.  There are so many other conditions that enter into this that nothing right on the dot accurate.  The first big one to consider is ambient air temperature.  Since the heater has to melt the solder in the solder pot, it will trip one helluva lot faster at 90 degrees F then at minus 10 degrees F.  So how much does this effect the motor overload condition?  It is all relative.  The values listed are all approximate, like within a given range.  If for some reason you need to be more accurate a different means of sensing current flow should be employed.  If you happen to use the newer European devices they are rated as a class 10.  Meaning to trip after ten seconds of a continuous overload condition.  All other factors being equal.
I hope this helped a little.  Just install the heaters corresponding to the motor nameplate.


----------



## Uglydog (Dec 15, 2014)

UncleRuss said:


> Mr. Dog:
> Lets back up a step or two for a minute to cover something we may have over looked.  Instead of trying to explain the whole picture lets do this:
> Remove the heater from either T1 or T3.
> Remove the two small screws holding the solder post.  When you pull it out you will hear and sense a snap.  This is the overload block tripping out just as it had tripped in normal use.  Look into the hole and you will see a horizontal piece of spring steel with a little dog leg bent on it.  This is what engages the ratchet wheel on the back of the solder post.  Now look in the hole for T2.  If the steel piece *is not *there the overload block was built to be a single phase unit.  If the hole for T2 looks the same as for T3 then just reassemble everything and when finished push the metal bar sticking out the front of the block to reset the block, thus closing the circuit through the overload block.
> ...



UncleRuss, 
This is a great explanation. Thank you!! This is the Starter that was on this lathe when I got her. The Thermals were missing and the post for the center leg was missing. 

When I pushed on the bar the tabs moved!!
I'll "just reassemble everything and when finished push the metal bar sticking  out the front of the block to reset the block, thus closing the circuit  through the overload block."

Thank you for helping me puzzle through this.
Daryl
MN


----------

