New capacitor install .?s

[Naiveambition]

A few weeks back my mill would spin, but not reach high speed. After finding the terminal block had melted, I soldered the wired together and the problem still exists. So on to capacitator issues. I had much trouble finding these. With it being Chinese the only exact option was Hong Kong direct.

My new ones are the same rating, except for the hookups. On the old ones both are wired direct in the motor . Both wires are black & black.

The new ones are one wired ( red & black) and one with terminal blocks. My question is about polarity issues. The motor plate diagram is straight up wrong so no help there.

So wandering if someone can show me how can I confirm my wiring is correct.

 

[canadianhorsepower]

The new ones are one wired ( red & black) and one with terminal blocks. My question is about polarity issues. The motor plate diagram is straight up wrong so no help there.

So wandering if someone can show me how can I confirm my wiring is correct.

according to the picture they are not the same value ????????
they are starting capacitor so the wiring doesn't matter any wy you want is good

 

[BaronJ]

They are not polarity sensitive, however make sure that you sleeve the terminals on the one with screw connectors. I would use heat shrink on there, after you have fastened the wires, of course.

 

[gus]

Microfarad wise,the replacement must be same value. Too low mfd will not start motor. My experience with Teco Taiwan Motors,the normal mfd would 250---300. Taiwanese Caps are reliable. Some multifunction Multimeter could read capacitance value. As a capcitor age deterate,mfd goes down.
Please check if motor is cap start only or cap start/cap run. The cap run capacitor is normally about 8---10 mfd. The start cap 250----300 mfd. Good Luck.

 

[Naiveambition]

The pic is for both the new ones. Motor has start and run caps. It is single phase double cap. Induction motor. Machine is a zx45 mill drill with 1 hp motor.

I'm hoping to not blow my motor up since I need it to make a new flange for an American motor of my choosing so I can source parts locally. If these caps don't fix the problem, not sure what I'm gonna do

When ordering, the site gave two options for wiring. One needed correct polarity and then their we're universal ones. I believe the grey one is universal since there is no polarity markings on cap, but the other wired ones I'm not sure.
These caps are the same as the previous ones as per ratings.
The grey one did cause some confusion for the uf rating, but web info stated that microfarads and uf rating were the same thing.

Is there ways to use an ohmmeter to verify or just wire them up and hope for the best

 

[BaronJ]

Just connect each new capacitor to the wires that the old one connected to. As I said earlier, they are not polarity sensitive. Usually if the wires are colour coded, the black wire indicates the outermost foil or plate of the capacitor.

 

[Coomba]

Capacitors have one side powered hot. Capacitance side to motor. If you have a VOM you can check the wires to find out which one is hot. My guess would be the black wire on the cap. Would go to the hot wire. I have seen motors run backwards if wired incorrectly. PM me if you don't get it going.
.

 

[Cogsy]

I had a similar issue with my lathe. Got the exact spec replacement and had red & black wires, old one was both blue from memory. Decided it didn't matter and just wired it up. It works now, but first start for the day it makes an extended loud hum even though it's spinning. I stop/start it a few times in quick succession and then it spins up and humming stops. Then it works fine for the rest of the day. Not sure if my cap is backwards or something is wrong with the actual motor. I know not really a helpful post, just letting you know. Sorry.

 

[canadianhorsepower]

Capacitors have one side powered hot. Capacitance side to motor. If you have a VOM you can check the wires to find out which one is hot. My guess would be the black wire on the cap. Would go to the hot wire. I have seen motors run backwards if wired incorrectly. PM me if you don't get it going.
.

sorry Coomba

but this is the answer with the most miss leading information
Ive ever seen.
not ONE thing you say is wright th_wtf1th_wtf1

 

[BaronJ]

Hi Al,

From your description it sounds as if the centrifugal switch is sticking and not opening when spinning up. A stuck centrifugal switch will cause the motor to hum badly and get hot very quickly. This will eventually lead to the motor burning out. Stripping and cleaning the shaft so that the switch actuator isn't sticking should solve the problem.

Naiveambition, Simply swap the capacitors one for one and all should be well.
If your motor has a centrifugal switch, then it may be worthwhile checking that it works smoothly without sticking, though not all single phase motors have them.

 

[Coomba]

sorry Coomba

but this is the answer with the most miss leading information
Ive ever seen.
not ONE thing you say is wright th_wtf1th_wtf1

Well Sir, I have been working with capacitors for the last forty years. Maybe my explanation of how to determine the voltage leg coming off the mill was a bit obscure, but a capacitors have to be wired properly, with one side powered. In his case it looks as if, he has a electrolitic type capacitor which is usually marked on the negative. I don't recall him saying any thing about them being marked, but I do remember him saying the diagram was wrong. As for everything I said being wrong, I believe that shoe is on your foot. Also instead of coming out with the blow torch, perhaps you should ask for some clarification.

 

[canadianhorsepower]

Well Sir, I have been working with capacitors for the last forty years. Maybe my explanation of how to determine the voltage leg coming off the mill was a bit obscure, but a capacitors have to be wired properly, with one side powered.

Good thing, I've been teaching robotic engineering for 20 years
depending of what kind of capacitor he's using YES they must be wired correctly.

Coomba;281548]In his case it looks as if, he has a electrolitic type capacitor which is usually marked on the negative

you are WRONG !! a starting capacitor will NEVER BE A ELECTROLYTIC CAPACITOR it works in AC

As for everything I said being wrong, I believe that shoe is on your foot. Also instead of coming out with the blow torch, perhaps you should ask for some clarification

.

now that you know. I didn't need any clarification, but I'm happy that you read my answer KNOW you learn something

 

[Coomba]

Good thing, I've been teaching robotic engineering for 20 years
depending of what kind of capacitor he's using YES they must be wired correctly.


you are WRONG !! a starting capacitor will NEVER BE A ELECTROLYTIC CAPACITOR it works in AC

.

now that you know. I didn't need any clarification, but I'm happy that you read my answer KNOW you learn something

I can't say that you taught me anything, but I'm glad you agree!

 

[canadianhorsepower]

I can't say that you taught me anything, but I'm glad you agree!

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[Naiveambition]

First off can we not fight fellows, we all learn more if we work together to work out the issues.

Secondly thanx to all responses, they were needed

Also was able to get them hooked up today and mill is running. The grey one I just wired up random, the blue one was wired black to black and red to yellow. I found that after stripping wires, that both had one yellow line to terminal block and one black.

And a side note these were bought thru Sears to save others the trouble of looking around for them. I tried electric outlets, air conditioning, pool stores, industrial supply stores, and the place I bought the mill from, who said let me check and I'll call back, four different times( still waiting on their callback:wall

 

[makila]

Generally the three wire type capacitor connections for a capacitor start, capacitor run motor are:

Small capacitance for starting and running

Large capacitance for starting

You will need to test which wire has more capacitance than the other to ensure the correct orientation but I have seen these reversed due to the tolerance of some systems, but for the best efficiency, get it right.

The centrifugal switch comment above is correct, check the switch is operating or the motor might not last as long as it should. I have found a diagram that should provide some clarity. You will note that the switch will disconnect at about 75% RPM but how this works in a variable speed system using PWM is unclear, perhaps the centrifugal switch is not present in these types.

Steve

 

[BaronJ]

Hi Steve,

Single phase induction motors speed is determined by the mains frequency and the number of poles that the motor has.

Unfortunately in order to vary the speed of this type of motor you will have to vary the AC frequency of the supply voltage while keeping the voltage at that for which the motor normally requires. As far as I am aware there are no speed controllers for single phase induction motors. Though there is no reason why there shouldn't be.

PWM doesn't work on single phase induction motors. It will work just fine on a DC motor though.

Naiveambition, I'm glad that you have got it sorted now. The diagram that Steve posted is useful information, it would be worth retaining a copy for your reference.

 

[Coomba]

Rof}Rof}Rof}Rof}Rof}Rof}Rof}:fan::fan::fan::fan::fan:scratch.gifscratch.gifscratch.gifscratch.gifscratch.gifth_wtf1th_wtf1th_wtf1th_wtf1th_wtf1*club**club**club**club**club**club*

WOW!!! Chill out brother. if your still looking for that stick you lost. I have a good ideal where it is.

 

[GailInNM]

Because of the direction this thread has taken I am locking it to further posting.

Naiveambition: If you still need assistance with your problem please feel free to start a new thread and we will try to keep it civil.
Gail in NM
Administrator
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