Dc Motor Hum.....

[mattthemuppet2]

Didn't know what a choke is, looked at wiki:

In electronics, a choke is an inductor used to block higher-frequency alternating current(AC) in an electrical circuit, while passing lower-frequency or direct current (DC). A choke usually consists of a coil of insulated wire often wound on a magnetic core, although some consist of a donut-shaped "bead" of ferrite material strung on a wire. The choke's impedance increases with frequency. Its low electrical resistance passes both AC and DC with little power loss, but it can limit the amount of AC due to its reactance.

How do I size/select a choke?

thanks, Brian

that's a great question! no idea i used the one that came with an old treadmill and the one i just bought works with treadmills that have a similar hp motor. other than that hopefully an electrically competent member will chime in!

 

[chips&more]

I found adding a choke on one of the DC lines made a huge difference in hum on my lathe treadmill motor. I didn't realise what it was for until someone suggested adding it and I was glad I kept it on the shelf. I didn't have one for my second conversion (drill press) and it hums pretty loudly, so I ordered another choke off ebay for $14. I'll see if it makes a difference on this set up. Worth thinking about.

Was the choke used in the field or armature circuit? I think I can answer it myself and say the armature? Thanks in advance…Dave.

 

[mattthemuppet2]

there are 2 wires going to my motor, + and - . it's in series with the - wire, although i was told it doesn't make any difference which wire it's on.

 

[John Hasler]

that's a great question! no idea i used the one that came with an old treadmill and the one i just bought works with treadmills that have a similar hp motor. other than that hopefully an electrically competent member will chime in!

You probably want a choke with an inductance between 2 and 3 millihenries. The exact optimum value depends on the hp (more power->less inductance) and the controller design, It isn't critical to get it exactly right. The choke must be rated for the full load motor current.

 

[chips&more]

there are 2 wires going to my motor, + and - . it's in series with the - wire, although i was told it doesn't make any difference which wire it's on.

OK, thanks, it’s on the armature circuit then. Your motor has real magnets for the field, so that’s why you only have two wires.

 

[calstar]

Minarik 23001C specs

is the min speed all the way down?

what do the tags say on the 2 brown wires?

with min pot at 0 and control knob at 0 hum should go away

is the speed control rated for the motor amperage...it is a small controller

Brown tags are A1 and A2, controller is well within spec for this motor(see above), I may try adjusting the other pots. I'm calling Minarik tech later today, I'll post any pertinent info(i.e. chokes)

Link to more info on the controller and calibrations;
https://www.minarikdrives.com/documents/250-0387.pdf

I love projects like these, I start out knowing next to nothing about DC motors and drives and now I know a little bit more than next to nothing!!
Thanks to all that posted here, most likely others can benefit from the shared knowledge,

Brian

 

[TOOLMASTER]

once you put a load on you will have to re-adjust

 

[TOOLMASTER]

looking at your picture is the 90-180 switch all the way left?

 

[calstar]

looking at your picture is the 90-180 switch all the way left?

No, ll the way to the right for 180VDC

You probably want a choke with an inductance between 2 and 3 millihenries. The exact optimum value depends on the hp (more power->less inductance) and the controller design, It isn't critical to get it exactly right. The choke must be rated for the full load motor current.

FYI anyone



Brian

 

[calstar]

Spent about 20min on the phone today with a Minarik tech troubleshooting the controller with multimeter in hand, appears to be....... a bad controller! I had him listen to the hum on the phone, not good, as well as the fact that the inhibitor is not cutting current from the motor. He told me to contact Galco(vendor), send it back, get a new one and a refund for the bad one, they pay shipping both ways. I'll see how it all plays out but so far no problems setting it straight.

Brian