View Full Version : HSD Spindles

10-03-2006, 04:28 AM
I'm thinking of getting an HSD spindle (2.25HP) and am wondering how quiet it is. Has this spindle got an electric fan?

Any other comments relating to this spindle welcome.


10-03-2006, 04:42 AM
HSD are available with, or without electric fans. Those with fans are more pricey, and put out less power for the overall package size. I have decided to go for the noisier versions and do my own silencing as before.

10-03-2006, 04:45 AM
John, are you talking of the ATC (Auto tool change) versions that SB are offering? My comment above are for those with conventional ER25 collets.

10-03-2006, 05:06 AM
Thanks for the quick reply Gerald. I'm thinking of a spindle with regular collet. I'm having enough trouble getting to grips with spindles, never mind ATCs.

Why is getting info on spindles so difficult? A search for info on the HSD website
shows fan cooled spindles on the larger models and liquid cooling on the rest. Liquid cooling sounds interesting, but again is a complication I can do without.

I'd hoped to see details of your silencer on the MechMate forum, but can see nothing. Is this something not completed yet?

10-03-2006, 06:16 AM
It is "completed" and has run fine through winter. Summer is approaching and time will tell if the spindle shuts down due to overheating.

Don't have photos to hand, but I found the development drawing of the bit of sheetmetal I used to make a duct/housing between the Pabst fan (http://www.talkshopbot.com/forum/show.cgi?tpc=7&post=29444#POST29444) and spindle:

All bends are 90 degrees, all inwards. Finished item is 90mm square, 40mm high. Pabst sits on wide-spaced holes. Bottom 4 holes screw to spindle in place of the original plastic cover.

On this page...
...you can see the original black plastic housing in one pic, and then the Pabst fan with chrome grill in later pics.

(When I tried to removed the original plastic fan from the spindle, it broke - I can't go back to that option)

10-03-2006, 07:43 AM
Gerald, for some reason I thought that some time ago you'd told me you'd made a silencer (from neoprene tube I think) and I was confusing this with you're fitting your own electric fan (which you also told me you'd done). It might have been somebody else who suggested making a silencer.

Now I see the photo I think "Why not?" Does it continue running after the spindle stops or anything fancy like that?

10-03-2006, 08:31 AM
It just runs all the time - nothing fancy. For the next spindle (with an intact fan) I want to try a sponge tube - it might save me some trouble.

Also, having seen some more pics of Colombos with this Pabst fan, it would appear that the fan housing allows some air to flow over the outside of the spindle. My duct is maybe too technical, and a non-tapered box could well be the best and easiest option.

I must emphasise that the thermistor and thermistor relay give me the peace of mind that I won't cook the spindle while messing about with its cooling.

10-03-2006, 06:32 PM
I have the HSD 2.25 Hp spindle. To answer your origonal question - it is not silent but it is very quiet. It is much quiter than a router. It does have an electric fan.

10-04-2006, 01:32 AM
Phil, is there a model number (and power curve number) stamped on the nameplate? (This will help to figure out its max speed and bearing type etc. A 2.25HP electric fan spindle is not immediately obvious from the HSD documentation. I guess your spindle is a MT1073-60 EL ER25 18000rpm?)

Also, was there a wiring diagram? (There should be 7 wires and a ground?:
- 3 wires for the 3 main phases
- 2 wires for the fan
- 2 wires for the thermistor)

The reason for my interest in this is because I have 2 spindles on order from HSD and I am finding the preliminary info a little confusing. What I am getting is "Electrospindle MT1073-140 collet ER25 18.000 rpm 3.5 KW, 380Volt, 2 poles, with coaxial fan, complete of ring nut and female connector.Drawing: Y616107319Power curve: 78"

10-04-2006, 01:22 PM
I purchased the 4HP 220V 1PH from ShopBot and the plate indicates it is a
MT1073-140EL-ER25-220V DX 18\18000 3.0KW
It is electric fan cooled.

Coming from VFD there are:
3 wires for the 3 main phases (I guess the VFD converts my 1ph to 3ph?)
2 wires for the fan (the fan is 220V 1PH and the power is take straight off the

10-04-2006, 01:43 PM
Thanks a lot for that info Evan!

Strange, when I asked them for an electric fan (EL part of the number) version for the 3.5kW MT1073-140, they offered a slightly shorter armature MT1073-120 instead, which was way down on power. I didn't think they had the 140mm/EL combo like you have, and I see that is already 20% down on power compared to my MT1073-140 with co-ax fan. Are electric fans less efficient and compels them to reduce power, or is the fact that you have 220V while my one is 380V.....? It's a mystery....

The actual spindles are all 3-phase, your guess on the VFD converting 1ph to 3ph is correct.

Where did you connect the thermistor wires to?

10-04-2006, 02:10 PM
I must confess it came pre-wired from SB. And I just went and looked at it again and realized its a total of 7 wires INCLUDING ground.

5 wire shielded cable:
3 wires for the 3 main phases
1 wire that is spliced into two wires that come off control out put of the VFD

10-04-2006, 03:13 PM
Evan, that sort of confirms that SB ignores the thermistor. I wouldn't want the heat gauge of my car to be disconnected.

10-04-2006, 03:38 PM
Thanks for the info on the fan Phil & Evan.

Gerald, when you say ShopBot are ignoring the thermistor, are you saying one is fitted but not used? But presumably could be connected?


10-04-2006, 05:06 PM
The thermistor in your HSD spindle is connected to the multi-function input terminals in the VFD and programmed for a N.C. connection. If the thermistor opens the drives is faulted and EF4 is displayed on the drive. One wire should be connected to MI4 and the other to DCM. These are wired and the appropriate programming is taken care of before leaving our facility.

The wires that come out of the orange servo cable are:

1 Ground wire
3 wires for spindle power
1 shielding ground wire
2 wires for thermistor

Please feel free to email me if you have any other wiring or programming questions on the HSD spindles that we sell.


10-04-2006, 06:55 PM
My apologies to all The road to hell is paved in good intentions. I took an even closer look and the two wires I thought were spliced together, they are actually wrapped together in shielding coming out of the heat shrink tubing on the end of the Orange servo cable. They are of a different gage than the other wires in the cable, part of my confusion. They are connected in the VFD just as Gordon reported they should be. I was not trying to make any sort of positive or negative comment on the wiring of the HSD spindle supplied by ShopBot. I am very happy with my HSD spindle and am thinking of getting a second one for my second Z. Ill be much more careful in the future. Again my sincere apologies for any confusion I caused.

10-05-2006, 02:52 AM
Gordon, you appear to be using thermoswitch terminology "...for a Normally.Closed. connection. If the thermistor opens... ". I am still concerned that the difference between a thermistor and a thermoswitch (klixon) has not been picked up. Another thread. (http://www.talkshopbot.com/forum/messages/7/13585.html).

The Delta folk told me that I could not connect a thermistor directly to their drive and that I would have to get a thermistor relay to put in between. I see that some Yaskawa drives can accept a thermistor directly. (Page 75 of this manual (http://www.yaskawa.com/site/dmdrive.nsf/(DocID)/MNEN-5JLRKH/$file/TM.E7.02.pdf#search=%22yaskawa%20e7%20programming% 20manual%22)) A properly matched resistor would have to added as well?

(Terminals M14 & DCM sound like Delta, while Evan has a Yaskawa?)

10-05-2006, 03:41 AM
These (http://www.thermik.de/pdf/ptc.en.pdf) Thermik thermistors are used by HSD. A good "thermistor relay" ensures the following:


I have a Siemens 3RN relay at the moment, and I see that it puts 2V and 5mW to the thermistor.

If I were worried about external bearing temperature, I could strap another thermistor on there and wire it in series with the internal one.

10-05-2006, 12:19 PM

You are right the connections above (MI4 & DCM) are for a Delta VFD. The thermistor connections to the Yaskawa VFD are S4 and SC. As for the connecting a Colombo spindle to a Delta VFD and them not being compatible you will need to talk to PDS-Colombo about that. They wire the spindles to the Delta VFD according to their specifications, program and test them before shipping them to our customers. I will need to ask them this question directly.

This exert from the MT1073 manual is all the information I have at the moment on the "thermistor" that is installed in the HSD MT1073 spindles.

A PTC thermistor is installed in the stator windings to monitor temperature. Electrical resistance from the thermistor
increases rapidly as it reaches trip temperature (normally 100C or 130C depending on the model).
The signal from the thermistor must be fed to a control device to stop the machine in order to protect the electro-spindle
from the effects of overheating.
Thermistor trip temperature depends on the model of electro-spindle. (See the relevant attachments.)
The thermistors used in these electro-spindles comply with DIN 44081-44082 standards.
Temperature Resistance curve
according to DIN 44081/44082
Figure 1.4
Main specifications
Nominal trip temperature
TNF= from 50C to 200C
in steps of 10K or 5K
Characteristic values for
PTC thermistors Resistance

10-05-2006, 02:19 PM
S4 on Yaskawa appears to be a "digital" input and unsuitable for an analog device like a thermistor. (I don't know which Yaskawa is being used - the E7 manual (linked above) mentions "analog" inputs for a thermistor).

I have mailed you the info I got from HSD re their thermistors, but they are the typical/garden variety conforming to Euro Norm 44081/2.

10-06-2006, 01:06 AM
An op-amp and a few resistors could be used to convert an analog signal to a digital signal. Since the thermistors that I've used in various designs have had almost linear output voltages based on temperature, the op-amp's comparator circuit could be biased with a resistor(s) to instantly swing the op-amp's output to a digital 'active' level. Total cost for components would probably be less than $2.00 at a Radio-Shack type store.

10-06-2006, 02:27 AM
Mike, these standardised thermistors are non-linear, but in a good way. Their resistance increases dramatically from 550 ohm to 1330 ohm when exposed to temperature within 5 degrees C of the thermistor's nominal "trip" temperature. (These numbers are standardised by the EuroNorms).

I entirely agree with you that a circuit which detects this jump in resistance should be very cheap, but I am trying to protect a $700 spindle so I bought the cheapest brand-name thermistor relay (http://images.google.com/images?q=thermistor+relay&ndsp=20&svnum=10&hl=en&l r=&safe=off&rls=IRFA%2CIRFA:2006-24%2CIRFA:en&start=0&sa=N) (already packaged & calibrated) I could find, and the Siemens 3RN cost me about $100 out here.

The way that SB connects these thermistors to VFD's worries me because I don't know if the VFD's multi-function digital inputs will see 550 ohm as "closed" and 1330 ohm as "open". I am guessing that the VFD sees both those values as "closed" and therefore a hot spindle won't trip the VFD when it should.

Why have motor/spindle manufacturers moved to thermistors instead of thermoswitches? Probably because:
- they are much smaller (typically 1/8" as opposed to 3/8") and cause less of an intrusion into the tight windings inside the motor.
- they are extremely reliable and don't deteriorate with time or repeated switchings (no moving parts)
- and it seems that they are cheaper.

10-06-2006, 08:07 AM
Done a little more homework. Seems that standard thermistor relays trip at between 3100 and 3600 ohm and reset at about 1600 ohm. This allows the temp to go 15 degrees over nominal on a single thermistor. If more thermistors are connected in series, the trip temp comes down.

10-06-2006, 08:37 AM
Gerald, the non-linear output of the thermistors that you've described is a big plus. Because a digital circuit is basically a binary analog circuit, with LOW being 0 to 0.7 volts and HIGH being 2.2 to 5 volts (when using 5V as VCC), a non-linear analog circuit with high-gain in the critical part of the temperature range could be constructed as a voltage-divider circuit, and effectively become a digital circuit. (Back in my days designing process control circuits for photo labs, I often used the circuit that I'm describing to control the heater temperature in the film/paper dryer cabinets where variations of 10-degrees F. were not critical. However, in the chemical temperature control circuits, where the temperature had to be held withing 1/4-degree F., I used commercial units like the Siemens unit that you listed.) Spending $100 to protect a spindle seems like a wise thing to do. (Since installing my 3hp Colombo spindle, I've decided that most of the 'optional' equipment that 'might' be necessary for proper operation of the spindle should NOT be optional because - in my case - it was required to reduce EFI to acceptable limits in a residential area. In my part of the world, summertime temperatures are usually moderate enough that I don't have to worry about things getting too hot except for a few extra hot days. Down where you're located, I can see how temperature would be a major consideration.)

10-06-2006, 10:04 AM
Mike, does your Colombo have a switch or a thermistor? I have already stalled my spindle and tripped the thermistor. It doesn't really matter how hot the day is, but rather how careless one is to answer the phone without stopping the machine.....

Cape Town does not get as hot as towns further north, near the Kalahari desert. (We even have a town with the onomatopoeic name Hotazel). But the ocean around here is cold and that keeps our town's temps moderate.

10-06-2006, 12:10 PM
Gerald, as far as I know, the Colombo has neither. I'll have to pull the cover off the VFD and see how many wires go to the spindle. When I installed it, over a year ago, I simply checked that all of the screws were tight without even counting the conductors. The only connections that I'm sure of are the three legs of the 3-phase power, a ground wire and two conductors to the external fan. When I get back to the shop I'll have to take a look inside the VFD.

As far as shop temperature goes, I get really nervous when it get above 105 F. inside the shop. Even though 100 is a hot day here, my lack of air flow through the shop can let the heat build up quickly. Since I don't like running the spindle any hotter than 120 F, a fifteen-deqree margin is pretty slim. On those hot days I tend to take shallow cuts at more moderate speeds than on cooler days.

01-13-2007, 05:34 PM
has anyone used ekstrom carlson spindles. i am looking for some feedbackhttp://www.ekstromcarlson.com/