We are committed to personal service.   Give us a call!
Phone: 574-288-4731    Fax: 574-282-4860

Electric Motor Diagnosis

My A.O.Smith Motor eats Governor assemblies?

PDF Print Email
Electric Motor Diagnosis
One of the best selling points about A.O.Smith single phase motors is that they have constructed them with the switches needed to start the motor on the outside where they can be serviced without dismantling the motor.   The switches can be adjusted easily and even replaced without even removing the motor from the device it drives.  This was a great innovation that quickly moved A.O.Smith into a class above most of it's competitors.   What many people don't realize is you can tollerate a great deal of bearing noise as long as the motor keeps running. The vibration from a slowly deteriorating bearing is responsible for wearing into the ears that retain the springs that make the stationary switch operate and even hold it's parts together.   If you are replacing the governor assembly too often chances are you have a bearing that needs replacement also. We sell the parts and are willing to coach you concerning any of your motor , pumps, & electrical equipment needs . Contact us!
 

How can I identify the cause of a noise?

PDF Print Email
Electric Motor Diagnosis
It may seem rather crude but a long blade (12") flat screwdriver with a platic or wood handle can be a valuable tool in tracking down a noise in any kind of rotataing equipment.  The length of the blade keeps you a safe distance away from getting caught in the rotating shaft & at the same time allow you a solid object to transmit the noise to where you can hear it. If you place the flat blade end on either end of a running motor & bringing the handle to where you can place your "best" ear onto the handle you wil be able to pin-point which end of the motor most transmits the noise you are hearing.  Apply the same method to each end, the center of the motor housing, the base on which the motor is mounted & then determine where the noise resonates the loudest.  This will help you determine where to begin dismantling or at least give you valuable information in the event that you are plannning to call and ask for advice.  Contact us if we can be of further assistance
 

What causes rust colored powder near the pulley or bearing?

PDF Print Email
Electric Motor Diagnosis
Most of the time the rusty powder is evidence of metal erosion due to 2 metal parts that are moving against each other causing small particles of metal to be rubbed away and the discoloration happens when these oxidize.  Often a loose set screw on a pulley will allow that pulley to get loose creating a noise and this erosion. Likewise, when a ball bearing gets loose in it's housing the same erosion occurs inside of the motor but the red powder will often show evidence on the outside of the shaft  opening.
 

Symptom: The motor hums but won't start.

PDF Print Email
Electric Motor Diagnosis
If the motor hums, it sounds like it is time to teach it some words...or perhaps there is another problem. Humming often indicates frozen bearings or bad start  capacitors. With the power off attempt to rotate the shaft. If it does not move freely or seems significantly  loose and wobbly the bearings are likely the culprit. If the bearings check out, then it is time to determine if the capacitor is failing.  Starting capacitors are usually black plastic cylindrical shaped with metal terminals on one end.  There is usually a small 1/4"round tan colored window between the terminals that is made of a flexible membrane designed to rupture if an internal failure produces pressure.  The first thing to do is look at this membrane to see if it either has a pin-hole or is blown clear open.  (On occasion the whole top will blow all of it's contents eliminating any doubt of a failure.) Beyond the obvious physical evidence capacitors can still look fine and yet be bad.  It requires a capacitor tester to check them otherwise.  I f you happen to be lucky enough to have another capacitor you can carefully substitute another one long enough to see if the motor will start. WARNING: only a capacitor of the same value (ex 161uf- 120v) may be trusted to permanently start your motor.  Each capacitor has 2 ratings one called micro-farad (abbreviated "uf")  and then voltage (abbreviated "v or vac")  You can always use a capacitor of a higher VOLTAGE rating than the original but should always strive to stay close (within10%) of the "uf" rating. Contact us with any other questions we'd be happy to help solve your problem!
 

Bearing Failure

My Blower motor Hums, Spins free but won't run?

PDF Print Email
Bearing Failure
One of the most common problems in furnace blowers and light duty motors that use an all angle sleeve bearing is that as that bearing wears and becomes looser the magnetic field that makes the rotor assembly go around is able more easily to pull that rotor assembly against the stationary iron preventing it from rotating while power is applied.  The easiest way to determine if this is the issue is to firmly grab the motor shaft while holding the motor against a bench or allowing the mounting to hold it, and see if there is movement side to side or up and down against the side of the bearings.  NOTE: it is normal for the shaft of these motors to have end play- that is to be able to push the shaft in toward the motor or pull it out slightly, however there should be no play side to side.  One other possibility for the failure of these motors to run, while humming, is a bad motor run capacitor.  If there is an externally mounted capacitor on this motor, you can easily remmove it & bring it in we will be glad to test it for you.  
 

Three Phase Windings

Should I replace small three phase motors or repair them?

PDF Print Email
Three Phase Windings
Most customers replace small three phase motors if they are standard frame sizes and replacement cost is low.However,special OEM motors or servo motors can usually be repaired more economically than they can be replaced,especially  if the problem is  only mechanical, such as bad bearings .If the windings are bad,we can also rewind your motor.At Enyart Electric we use higher quality materials than most manufacturers and pay attention to details that production line workers just can't watch.We rewind all types of electrical apparatus, so feel free to contact us for all your rewind needs.
 

Can inverter duty motors be rewound?

PDF Print Email
Three Phase Windings
Yes, inverter duty motors can be rewound.The biggest enemy of inverter duty motors is a corona buildup in the winding.This buildup is produced by the inverter pulses and causes corrosion between turns.This  leads to insulation breakdown  and failure of the winding.Knowing this we can insulate accordingly and produce a good inverter duty winding. At Enyart Electric we use pulse shield wire and high quality insulation in all our rewinds so using inverters is no problem. Please feel free to Contact us  if we can help you with any questions.
 

How Do I Connect A 9 Lead Motor ?

PDF Print Email
Three Phase Windings
The most common 9 lead motors are commonly known  as one & two star conncetions.  This is the most common connection for motors from fractional to 15-20 hp.  The lead numbering is very simply, 1,2,3,4,5,6,7,8,9.  It is always advisable to look carefully at the motor nameplate and inside of the junction box cover for a connection diagram, however if you can't find one grab a continuity tester or ohm-meter and seperate the 9 leads so that none of them are touching and see if the following leads have circuits:  1&4, 2&5, 3&6, then 7&8&9 should all cause your meter to move.  There should be no other circuits.  If this proves true then you can connect these leads as follows to run on 230V :  L1 & 1&7,   L2 & 2&8,  L3 & 3&9 then tie & insulate 4&5&6.   to run on 460V:  L1 & 1, L2 &2, L3 &3, tie and insulate 4&7,   5&8,   6&9  If all 9 leads test as if they have continuity and the horsepower of your motor is lower than 20 then it is likely that you have a "Delta Connected Motor"  : for 230V  connect L1 & 1&6&7,  L2 & 2&4&8,  L3 & 3&5&9.   For 460V  connect: L1 &1, L2 & 2, L3 &3, tie and insulate 4&7, 5&8, 6&9.    If the result gives you anything but the desired results give a call & we'll be glad to work through the options with you.  Contact us.
 

How Do I Choose the right Amperage Motor Protection?

PDF Print Email
Three Phase Windings
There are several factors to consider when deciding how to properly protect an electric motor winding. If a readable nameplate is availble there is a category indicating FLA or full load amperage. This is the maximum amout of amperage that this motor should draw on a constant basis while driving it's load.  There are most often 2 entries that correspond with 2 different voltages. Let's say that your motor may be operated on either 230Volt or 460V  listed like this "230/460"  at a position very near on the nameplate you also see Either "A" or "Amps" followed by 30/15 the relative position of these values indicate that if operated on 230V the motor will drw 30 amps or if operated on 460V it will draw 15 amps.  Make certain that you know what voltage you are running on.  One important fact to know about motor circuits is that any electric motor will draw 5 to 7 times it's rated amperage during the period that it takes to climb from standing still to its' rated speed.  So the motor above for a period of 1-2 seconds will draw 75 to 105 amps until it levels out to it's running speed. This is the reason that fuses for motor loads must be time delayed fuses or protected .  They must allow for a short-term high in-rush of c urrent and then begin moitoring the motor for a long term amperage of 10% more than it's full load rating.  So in the case above a 15 amp motor should be protected for  16.5amps.  There are many factors such as temerature and slower starting loads such as blowers that complicate this question . If you would like to discuss your motor feel free to contact us, we'd be happy to help answer your question.  Contact Us
 

Can I determine Why my three phase winding burnt?

PDF Print Email
Three Phase Windings

In a short article it would be difficult to give an exhaustive answer but there are some common winding failures that leave very specific evidence. After removing one end of your motor, blow dust or dirt off of the windings so that you can see the copper windings as an assembly. If the entire winding (full circle is roasted dark brown or black then the motor was likely overloaded. If there is a pattern where there are 3 or 4 darkened coils next to 6 or 8 normal looking coils and this pattern is repeated uniformly around the entire circle then your motor was receiving power on only 2 of the 3 power lines, (known as a single phase). Causes of a single phase conditions are often as follows, 1 blown fuse, 1 pair of bad contacts in a 3 pole contactor, 1 burnt off wire, 1 wire-nut that worked loose and let a wire escape it's connection. It's critical to find the source of such a failure before allowing a new motor to fail from the same poor source. Other failures are isolated burnt slots out on the circumfrance of the winding where the copper cut through the slot liner & finally blew to the iron laminations, and our all time favorite the mouse or rodent that took one bite too many & whitened his teeth for the last time. Most of the other failures leave irregular evidence of carbon that raise more questions than they answer. Lightning is a common reason that a winding will blow from it's copper to the stator iron. If you have any questions we'd be glad to discuss them with you. Contact us .

 

Single Phase Windings

Are There Standard Connections for Single Phase Motors?

PDF Print Email
Single Phase Windings
Single phase motors vary as much as their respective applications.  There are a few common numberings that may address quite a few single phase applications.  If the wires in a single phase motor have numbers either printed on the wire-jackets or tags wrapped around the leads 70% of the time 1,2,3,&4 are Main Winding leads and indicate that this motor may be operated on 115 or 230V.  The most frequent numbering for the Auxiliary or Starting Winding is #5 & #8,   .  If this motor only had 6 leads they would be connected as follows, for 115V  L1 would feed #1 & #3 & #5,    and  L2 would feed #2 & #4 & # 8   this motor could be reversed by interchanging #5 & #8.     To run this same motor on 230V : L1 would feed #1,    then #2 & #3 & #5 would be tied together & insulated and L2 would feed #4 & #8.  this motor would also be reversed by interchanging #5 & #8.   The issue becomes slightly more complicated when the manufacturer adds an overload protection device in the junction box and eliminated lead #1  directly attaches #1 to the overload and brings 2 additional leads with more arbitrary nnumbering  such as P1 & P2 or J1 & J2  .  If you will apply yourself to the task you can probably analyze the remaining leads to see what leads still remain.   Usually P1 becomes the replacement for #1 and is fed by L1 & any leads that would have been connected to #1 in the previous description will now be hooked to P2 and in doing this the winding is interrupted in the event of an overloaded condition- shutting down all windings thus saving the motor against a failure in the device the motor is driving.   If it's more confusing than I just described feel free to give me a call I'd be willing to help decipher what you have. Contact Us  
 

What if there is a burnt odor coming from my motor?

PDF Print Email
Single Phase Windings
First of all there are more than one possible causes for a burnt ordor. If we are talking about a capacitor start motor, capacitors often fail & will let off a foul odor  that resembles something electrical burning.  Usually the capacitor will blow it's contents out of the case or at least rupture the 1/4" membrane on it's top. However if the capacitor appears fine removal of one end of the motor will expose the copper windings and allow you to inspect that copper for signs of discoloration and burning. Whether single phase or three phase, discoloration and or evidence of carbon is a good indicator of a burnt winding.
 

Login