Simple turbo pump controller

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Alexi Hammond
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Re: Simple turbo pump controller

Post by Alexi Hammond »

Hi Rich,

Yes, the pump gets barely warm after many hours of pumping. However, I left the fan on the pump anyway. The fan seems to be made for 208 or 240V AC. It runs on 120V AC very slowly, but that is enough to keep the pump cold.

Alex
richnormand
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Re: Simple turbo pump controller

Post by richnormand »

I received the eBay frequency meter and here it is.

Just wire the +5V, grounds and signal from pin 3 of the 555 timer in Alexi's controller. You can follow the pump ramp up and slowing down from reading its frequency (1500 Hz is 90,000 rpm). Not bad for $12 and free shipping.
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Richard Hester
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Re: Simple turbo pump controller

Post by Richard Hester »

I may try a simple controller as well, as I have an Alcatel 5010 drag pump coming in the mail, as well as one of uncertain pedigree already in house. If anyone has a copy of the manual, for this one, I'd appreciate it. Otherwise, I'll try contacting Adixen/Alcatel.
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Re: Simple turbo pump controller

Post by AFW »

Alexei
Thanks for the controller circuit. I notice that on the TPH 055 diagram there is a contact "D" that doesn't have a corresponding connector on the controller. Is this contact left floating? Also, contact "E" is labelled as 15V, but is connected to the +5V line of the controller. Is this a misprint in the TPH055 diagram?
UK purchasers of these pumps should remember that they will have to pay VAT, which, with postage, brings them to about £100. Still a bargain , though.

Tony Webb
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Re: Simple turbo pump controller

Post by richnormand »

I think the D to F is a variable resistance as the temperature sensor. I did not connect anything to the D terminal. I'll monitor its value next time I ramp the pump and see what happens. It's most likely used with the OEM controller to ramp down or shut down the pump in case it is overheating .

Hall effect sensor for rotation (E) works fine with 5V in my setup, as stated in Alexi's diagram.

Alexi will probably know for sure.
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Alexi Hammond
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Re: Simple turbo pump controller

Post by Alexi Hammond »

Correct, the pin D is connected to the temperature sensor. When the pump overheats above 50C, resistance between pins D and F drops and the OEM controller shuts down the pump.

The UGN3077 Hall sensor IC has a built-in voltage regulator and works fine with 4.5V to 24V supply voltage.

Alex
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UGN3077.pdf
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ggombert
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Re: Simple turbo pump controller

Post by ggombert »

Has anyone located a source for the connector on these pumps?

Glenn
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Re: Simple turbo pump controller

Post by gpecke »

The connectors for these and the Adixen pumps can be found in the Canon catalog. They have to be
ordered as shell and parts.

Seemed to be a nuisance to order a small quantity of these.

I used crimp connect gold plated single pin connectors crimped onto a ribbon cable and insulated
with heat shrink. This is very quick,cheap and easy to do, and the ribbon cable is neat and easy to handle.

The part I used is at http://www.electusdistribution.com.au , part no. hp1260.
Chris Trent
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Re: Simple turbo pump controller

Post by Chris Trent »

I have modified this circuit with a L298 H-Bridge in place of the mosfets. In my case the purpose was to drive the a single phase Molecular Drag pump with no center tap, but the addition should work well for most of the rest of you.

The local electronics surplus shop had a whole box of them, so for me it was an easy call.

In addition to being able to run without a center tap, it adds a couple of nice features; you can add an additional switch for fast motor shutdown, and sense resistors for current control.

I'm planning on posting the modified schematic soon.
DSchultz
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Re: Simple turbo pump controller

Post by DSchultz »

I purchased 20 pieces of the RFP2N08L from Quest Electronics, if anybody wants a pair of them please get in touch with me.
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Re: Simple turbo pump controller

Post by ggombert »

Below is the link from DigiKey for a IRL520NPBF logic driven MOSFET that should work well also as a replacement part. The current price for qty1-9 is $1.24. The data sheet can also be downloaded from the link below.
Glenn

http://search.digikey.com/scripts/DkSea ... 520NPBF-ND
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Re: Simple turbo pump controller

Post by Chris Trent »

I've made a few other changes to the setup I'm using.

First, you may recognize that I simplified the design a bit by using a Full H-Bridge L298 IC.
The Full bridge lets me run single phase pumps that aren't center tapped, as well as get more torque out of those that are. Both circuits in the L298 are used in parallel to increase the power handling capability.

Instead of using Nand gates to power on and off the control signals, I am using the built in enable pin on the bridge. Since the bridge is turned on or off directly I was able to dispense with the Nand (NOT) gates near the end of the circuit. I could have done away with the Nand gates entirely, however I chose to keep the first two and connect them to an interlock circuit. With this particular H-Bridge IC, having both inputs set to the same value shorts the motor outputs to each other, creating a braking effect. I have taken advantage of this to create an emergency stop switch.

Other improvements include TVS diodes near the motor to protect the circuitry.
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ggombert
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Re: Simple turbo pump controller

Post by ggombert »

Hi,

I finally finished a pumping station based on Alexi’s controller and a TPH-055 purchased off of EBay. All of the vacuum fittings are from Lesker’s; the main gauge in the system is an MKS-901P which bottoms out at 10-5 mTorr (also another snag off of EBay). The gauge bottoms out about five minutes after turning on power to the turbo pump.

Most of the parts for the controller were purchased from Digikey and Radio Shack. I also included a cheap frequency counter on the front panel driven off of pin 3 of the 555 timer.

The only thing that I did to the pump was to use some fine grain sandpaper (as Carl suggested in his post) to smooth out some of the dings in the flange of the pump. I actually purchased two pumps of off EBay and both of them are fully operational after following the cleaning instructions (to get rid of the black gunk in the pump) and smooth out the divots in the top vacuum flange.

I will probably replace the grease reservoir in the pump too since it is not too expensive and seems like a modest investment to keep the pump in good working order.

Glenn
Attachments
turbostation.jpg
Andrew Seltzman
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Re: Simple turbo pump controller - CONNECTORS

Post by Andrew Seltzman »


The proper connectors for the TPH-055 pump and TCP 035 and TCP 015 controllers are:

Pump body connector: 12-8p or equivalent

Pump side of cable: 12-8s or equivalent (PT06E-12-8S)
http://www.alliedelec.com/search/produc ... U=70143407

Controller side of cable: Harting 09-06-231-6822
http://www.mouser.com/ProductDetail/HAR ... dkYPFT0%3d

Controller board connector: Harting 09-06-131-6922
http://www.mouser.com/ProductDetail/HAR ... RPspXXI%3d

Harting connector data sheet:
http://www.farnell.com/datasheets/26900.pdf

Good luck with the pump controllers, I'll try to build some boards with my CNC mill as time permits.

Andrew
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Jerry Biehler
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Re: Simple turbo pump controller - CONNECTORS

Post by Jerry Biehler »

If you are looking to make PCBs check out the dorkbotpdx board program. You get 3 quantity boards for $5 per sq inch. Very nice boards too, purple conformal, plated through holes and vias, very fine spacing, silkscreen both sides, and gold plating.

dorkbotpdx.org
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Re: Simple turbo pump controller - CONNECTORS

Post by Andrew Seltzman »

Also see an ebay auction for the same connector (pump side) for $7 each:
http://www.ebay.com/itm/300441579297?ss ... 1497.l2649

Andrew
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richnormand
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Re: Simple turbo pump controller - CONNECTORS

Post by richnormand »

Got a few yesterday. Many thanks for the e-bay link Andrew.
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Re: Simple turbo pump controller - PCB design complete and operational

Post by Andrew Seltzman »

I have designed a PCB for the simple turbo controller, and it is operational. The design constraints were: single sided PCB of 3"x2.875", using only 0.4" jumpers on the top surface. This board is a slight modification of Chris Trent's modification of Alexi's turbo controller. Grounding the motor center tap set the H-bridge and chips on fire(not sure why), these were easily replaced and everything worked again. The pump maxes out at 1.3khz(not sure why, it runs perfectly smooth) at 30V across the bridge and a 1 ohm vsense resistor.


turbo-control.brd - eagle cad board design
turbo-controlbd.nc - gcode drill file for holes units in mm
turbo-controlbot.nc - gcode mill file for traces units in mm

Pics as following:
3x PCB after milling
parts
test setup
hall sensor output
3x assembled board

WARNING _ WARNING: Do not close the top jumper above the turbo connector, everything will catch fire (to be fixed in rev 2) other then that, everything works fine although it only reached 1.3kHz rotation speed.

Andrew

Edit 10-21-2020 by Jon Rosenstiel: Control board files placed in zip file "Board design files".
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Board design files.zip
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Richard Hull
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Re: Simple turbo pump controller - PCB design complete and operational

Post by Richard Hull »

Nice work Andrew! You have opened up possibilities for many who are only able to snag a turbopump only in surplus buys. This sharing stuff really works! (Always has , actually)

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Re: Simple turbo pump controller - PCB design complete and operational

Post by Andrew Seltzman »

Some feedback from Alexie:
--------------------------------------

I just want to point out a few things which are wrong with Chris Trent's and yours controller circuit.
1. The hall sensor output (pin G) needs a pull-up resistor about 10k to +5V. Without this resistor the hall sensor signal looks horrible and might not trigger the 555 timer reliably.

2. Driving the turbo pump motor which has a sinusoidal back-emf proportional to its frequency with fixed amplitude square wave from an H-bridge is like trying to fit a square peg into a round hole. Something got to get hot: either the H-bridge or the pump's motor. You don't want either to get hot. Simple solution is to connect a 5 to 10 ohm resistor in series with the motor or in series with the H-bridge power.

3. If you are using the whole winding (pins B and C) then you need to double the voltage (at least 50V) in order to get full speed. Alternatively, you can use a halve-winding (pins A and B or A and C) with a 30V power supply.

4. The speed control circuit will work way better if you separate wires for the hall sensor from the wires for the motor windings (use two cables, not one) and use shielded cables.

5. Don't try to stop the pump by shorting the winding as Chris suggested. There is enough energy stored in the rotor spinning at full speed to melt the windings.

I hope that all those suggestions will help you to improve your controller.

Cheers,
Alexi


Some feedback from Rich Normand:
--------------------------------------
Hi Andrew,

I tried both Alexis and Chris circuits and settled on Alexis but with
replacing the current limiting resistor with two 12V H4 halogen lamps and
NTRs all in series. At the start the NTRs have large resistance and the
lamps low resistance, limiting the strat up current surge. As the pump revs
up the NTRs warms up and get down to about 2 ohms while the lamps start to
glow brightly thus limiting current and changing thier resistance depending
on current. At top speed they go back cold to a few ohms and the running
current keeps the NTRs slightly warm. Best of both worlds.

I also built Chris circuit and could not get my pump to go to top speed. I
think the issue is although the L298 chip can reverse the applied voltage
polarity the 28V for 100% duty cycle, but is only applied to the two coils
in series by the out2, out 3 and out1 out4 sequence, instead of in Alexis
circuit where the full 28V is applied to each individual coils in sequence.
Am I wrong here? If so running at twice the voltage might work but I did not
want to try!!!!

If the previous is true, grounding the center tap will result in mahem as it
will be at half voltage at any given time while the virtual ground is being
flipped at each half rotation.....

Perhaps a modification to take advantage of both topologies would be the
answer? Alexi's waste half the duty cycle by powering one coil at the time
so a merging of both might work even better?

Did not want to post any of this till checking with you since you have done
quite a bit of work with these.

Have fun.
Cheers.
Richard

--------------------------------------

I found the problem that was causing the driver to catch fire. I am using a 1ohm current limiting resistor, and each pump coil has a resistance of about 1.5 ohm. With both bridge drivers in parallel the maximum continuous current permissible through the bridge is 4A. At 24V with the center point grounded, if power is applied when the pump is at standstill, the bridge will be carrying 10A, which is why it will catch fire. If you ground the center tap and start the driver at 5V, it starts up just fine. For the long term we should have some manner of current limiting device in series with the motor power.

Obviously the motor needs a constant V/Hz drive scheme to limit start up current, which this simple driver is not capable of providing without a 10 ohm or so series resistor that will still dissipate power when the pump reached full speed.

What do you all think about adding a LM317 linear regulator in a current limiting configuration in series with the 24V bus? With a 1ohm feedback resistor this will limit current to 1.25A at all times and should have minimal losses at higher speeds.


Andrew
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Chris Trent
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Re: Simple turbo pump controller - PCB design complete and operational

Post by Chris Trent »

Thanks for the post. That high starting current surge explains a few things.

The circuit I was using works overall, but I toasted several iterations of it before moving on to a micro-controller based solution with over-current protection.

I'll post details on that later if I can get it fully up to speed.
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Re: Simple turbo pump controller - CONNECTORS

Post by DSchultz »

I can now confirm that Mouser part number 654-PT06A-12-8S-SR made by Amphenol fits the TPH-055 pump connector. Cost is $28.27


How is the PCB design coming along?

Dan Schultz
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Re: Simple turbo pump controller - CONNECTORS

Post by Andrew Seltzman »

Haven't worked much on the PCB, but I have solved the current limiting problem.

The following buck-boost DC-DC converter is available on ebay and has current limiting. This will allow you to run the turbo pump on any voltage between 5 and 35v input while preventing the initial current during startup from climbing too high. I tested this with the controller without using a resistor and it started to spin up fine. The next revision of the PCB will include a connector to use this converter to drive the h-bridge

http://www.ebay.com/itm/LM2596-LM2577-A ... 256facce20

Andrew
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Re: Simple turbo pump controller

Post by Roberto Ferrari »

Fellows

Can somebody provide me with the pinout of a TPH 050?
I don't know were the motor windings come out.

Thanks!

Roberto
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Re: Simple turbo pump controller

Post by Andrew Seltzman »

You have to look really close at the connector, each pin has a letter next to it. The first post in the thread has the pin connections listed by letter.

Andrew
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