Recent content by BobM2

What's the difference between a Hipot test and a meggar test? Don't they both apply a high voltage and measure (and limit) the current?

I'd like to check our motors with a Hipot test. The field wires are a bit close to the metal housing. The motors are universal and we run them on 115 vac 60 hz. I assume I should use an AC Hipot. When would one use a DC Hipot test?

Another question on Stressproof: Doesn't the cold working leave a residual compressive stress only near the surface? So if the surface was machined down, wouldn't you lose that advantage?

We currently use double roll pins to attach a gear to a shaft (5/16 OD with 3/16 OD Pin pressed inside). I need about another 30% shear strength. I thought about a heat treated 4340 solid pin for high strength but am worried about its shock resistance. Any suggestions on a good...

I'm guessing but I think PFj probably stands for Power Factor Joules. Our power company charges extra for low power factor loads. You might want to ask them. Ours was helpful in describing the terms.

I'm considering bring in-house some thread grinding work on our worms. Any recomendations on good machines for pitch diameters of 1.5" and less?

Is there wear on the teeth before breakage? Misalignment would tend to cause wear problems before tooth breakage problems.

I don't think solitzer is quite right. The units of his equation are in#in. A good approximate equation is that the axial load, F = Torque/2 * 1/R * 1/(tan(LA)). For example, if torque = 7.5 in#, pitch radius = .312" and the lead angle is 6 degrees, the axial force would be 114#.

Any recommendations on good books for fixture and tooling design for milling operations?

Well, this is a bit embarassing. I was counting the pins from the wrong direction on the right side so I had pins 6 and 7 mixed up. I should stick with gears and bearings. Thanks to all for the suggestions!

I'm using an MC34071 op amp with a "FlexiForce" load sensor connected per the drawing supplied by the maker of the load sensor (Tekscan): http://www.tekscan.com/flexiforce/specs_flexiforce.html. The output of the op amp goes to about +8.5 volts and won't change much (changes about .2 volts)...

Are you also constraining the bar axially? Under torsion the bar will want to shorten and you will also get tensile stresses.

Yes, the module is inside our control and the antenna is outside the control. I've tried ferite beads on the motor lead wires. I hadn't thought about using them on the control lines coming into the control. That would be an easy thing to try - Thanks.

The Linx device is the ES series, 916 Mhz, FSK. I think the noise is from the electric field produced by the motor. The motor is a universal type. The noise source is the brush/commutator sparking. The motor powers a winch. When lifting a load (high amps, low speed) the RF unit works well...

I'm using a Linx single chip receiver to control an electric motor. The motor puts out a lot of electrical noise. Shielding it helps considerably. I'm wondering what might be going on in the receiver when it cuts out. It acts like it might be going into saturation somewhere. The motor will...