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Very low out put ( 148 volts) for Stamford 590KVA/ 480volt 3 hphase generator

I believe I have a defective exictor winding. The 3 phase rotating winding of the exicitor is bad I believe. At no load I have 148 volt output from alternator, with 1 .8 amp exictor current and 30volts Dc out put from exictor. Does this exictor winding pull right of the shaft?? does 30 VDC out at 1.8 amps on exictor seem correct at no load.

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Check the windings for shorts. Also check commutator bars or rings to make sure none are grounding to the armature sharft or laminations.

If those all check okay check brush tension and wire connection integrity, try flashing the armature if the starting action is not performed though the windings, In other words if it has a discrete starter motor- flash the armature. If there are start windings on the armature, it gets flashed each time it is started.

Also double check the wiring of the coils because someone may have connected them wrong, out of phase, in parallel when they should be in series, etc.

At no load it should be higher- but it is also a factor of how the magnetic fields are building or decaying.

Also check to see if you have any capacitors for power factor correction- they may be shorting out.

Posted on Feb 19, 2012

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I have Hobart D300 mixer which operates at 220V, 3phase supply and whereas the facility has 208V, single phase supply. Is there any recommended phase converters available for this product. Thanks


Hi Bill
I may be wrong here......
But I've been around Electricity for a long time.
Have Never seen a device that does phase conversion.
A Building site or home will either have Three Phase or Single Phase Power Available
BUT...A portable (Hired) generator could be "three phase" and you could use any one of those phases individually or all three phases.

I have 3 Phase supply to my house!
But I use 230 volt Single Phase for appliances.
My Bore Pump uses a 3 Phase Motor,
(so with a voltmeter it would read about 440 vAC to the pump motor).
Some Further Info:
A GENERATOR is basically a motor used the opposite way. Rotate a motor and it Generates.
The Phases refer to the THREE Windings in the supplying generator in your suburb.
A Large Magnet passes each winding in sequence giving you the three ripples in the supply.
Our houses can choose to have 1 Phase or Three Phases from the street when you set up your electric supply.
So... to confirm, look at the wires on the supply poles to the premises. Usually three in our area (Oz)
Most people are not aware that a car Alternator is actually three phase. The Rotor is the magnet that rotates.
The only difference with an Alternator is that each "Phase" is connected to 2 Diodes (6 total) to convert the three phase to DC to charge the vehicle.
The Regulator controls the voltage to the Rotor, thereby controlling the output.
So.... An Alternator could in theory supply 3 Phase in a mobile generator. Custom Made. Constant speed would determine the frequency of 50Hz or 60Hz.
Not sure what country you are in

Hope this Helps or gives you food for thought!


Three phase electric power

Jul 08, 2015 | Hobart Food Mixers

Tip

Generator Not Producing Power ? Stator Winding


There are 4 requirements that have to be met before a generator is able to produce power. Due to number of questions that have been asked, a Coleman PowerMate 1500-1850 with a Briggs and Stratton Engine will be used here.

1) The Engine has to be turning at correct speed
2) Field Winding (Rotor) on the alternator must be energized
3) AC Winding (Stator) must create a voltage in presence of magnetic field
4) Output passes through Safety Devices before it reaches an outlet.

This Tip will cover the Stator Winding.

The stator winding is the winding that is around the outside of the rotor. It doesn't usually move. Previously, the alternator design was called a revolving armature, in which the field was stationary (outside), and the stator (armature) was the rotating member. This quickly was replaced, eventually, by the revolvingfield configuration, since the brushes carry a relatively small DCcurrent, rather than a larger AC current with destructive arcing. Brushes were prone to failure due to high wear.

In the revolving field architecture,there are primarily 3 types of alternators: Single Output, MultiOutput, and MultiPhase.

The single output alternator is just that, it outputs a single voltage. Typically, it will be either120vac (60Hz), or a single phase 240vac (50Hz) depending on the country it was bought in. The stator winding of this kind of alternator has only a single winding, with 2 wires coming off of it. One of these wires goes to the neutral bus for the outlets, the other wire goes to the circuit breaker, and the other side of the circuit breaker goes to the outlet. Disconnect both of the wires, and use your multimeter to check the continuity between them. You should have continuity here. Also check each wire to the frame of the alternator, there should not be continuity here though. If you don't have continuity between the wires, or if you have continuity between the wire and alternator frame, then you have what is called a grounded winding. This will have to be addressed by a motor shop, or replace the stator in its entirety. It is generally more cost effective to replace the generator though. Remove and sell the copper wire, and use that money towards a replacement generator.

Multiple Output alternators are usually found in the next step up from "bargain" generators. These usually will have an output of 120/240vac, and likely a low voltage battery charging circuit as well (12vdc being most common). The stator for these is checked in the same way as a single output, with a caution on the low voltage winding. On the low voltage winding,there will be a single diode (called half wave rectification) or a full wave rectifier (2 diodes) connected to the windings. You must disconnect at least 1 wire from the diodes to check the windings, and both wires to check for continuity between the windings and the frame of the alternator. If you don't disconnect the wire(s), the 1 way nature of the diode will indicate no continuity when there should be,and may cause you to not see continuity when there actually is (to the frame).

If the low voltage winding is open, the generator is still usable for the 120/240vac features. You just won't have benefit of the low voltage battery charging circuit, which is actually a very poor charger to begin with.

On a 120/240vac alternator, there may also be a switch that turns the 240vac on and off at the receptacle. This switch is put here so that the 2 120vac windings can be put in parallel for greater current capacity if 240vac is not required. If you have 120vac, but not 240vac, and the circuit breakers are not tripped, this switch is likely the culprit. It is just a double pole double throw switch that is easily replaced with one of the same type, and same or higher current rating. Never switch from 120 to120/240vac or vice versa while the engine is running. To do so invites winding damage due to arc-over, and may damage any devices that are connected from the voltage spike.

MultiPhase alternators are nothing more than single output alternators with a twist. Rather than having a single winding, there will be 3 windings, with a 120 degree phase separation. The in phase neutral wires will all be tied together, but the phase outputs will be separated, and connected to the receptacle in a specific order. This is called a Wye (Y) configuration. An alternate configuration is when the windings are all connected to each other, end to end style. The junction of each connection is then brought out to the receptacle. This is called a Delta configuration. Three phase / multiphase alternators will not be discussed in depth here as a much higher technical knowledge will be required.

As far as the stator winding goes, that is it. If you have continuity where you should, and don't have continuity where you shouldn't, the stator winding is likely good. As mentioned, if the low voltage battery charge winding is open, but not grounded / shorted to the frame, the primary function of the alternator is still usable.

If your checks of the stator are good,time to move on to the next tip.
Output and Safety Devices

on Sep 24, 2010 | Electrical Supplies

1 Answer

Where can i obtain a wiring diagram


A one phase 3 wire system has a center tap. Two hots and a neutral. Typical 120/240 volts.
A three phase 4 wire system has Three hots in a Y or Delta. The Y system has three hots and the neutral comes from the center of the Y, this is the neutral and grounded conductor, 120 volts from hot to ground and 208 volts hot to hot. In a 3 phase system the voltage is not doubled hot to hot as in a single phase system because the hots are 120 degrees phased from each other and the square root of 3 is the factor, multiply the 120 volts by 1.73 to get 208 volts hot to hot. Multiply 208 by the reciprocal of 1.73 and get 120 volts. Your exact application is not given so it is not known. A delta system is a triangle and the angle of each triangle is a hot wire, one angle would be grounded or the center tap of one of the sides of the triangle. Y is the configuration of the windings of the alternator or transformer and Delta is the configuration as a triangle of the windings of the alternator or transformer where the power supply is.

With a three phase home service, you can only connect two hots from your single phase generator, and the neutral. One of the house's hot does not get connected and any three phase loads in the house should be switched off and kept from energyzing or a circuit breaker or fuse serving that 3 phase load may trip.
Only one power supply can be connected at a time. The power company power must not be connected at all while using an alternate power supply unless your power supply has means to synchronize the alternating cycle.

It is adviced that the loads be kept within 10% of their rated voltage, especially motors.

May 04, 2015 | Heating & Cooling

1 Answer

I purchased a generac 22 kw 3 phase 120/240 volt generator. I was surprised to find that it had a wild leg. Can i change the leads on the stator output to eliminate the high leg and get straight 120/208...


This unit is wired 120-240V 3 phase Delta. if you are using on it 120/208V 3 phase application it will need to be re-tapped. If you are using it in a home 120-240V single phase it will need re-tapping, Do NOT just use 2 legs, as this will cause rotor imbalance and wear out the rotor bearings, and odd ball currents to flow. If there are 12 leads coming off the stator it can be reconnected. If not you are stuck with it, except by using a transformer

Dec 15, 2013 | Generac Generator QT02224JNAX QuietSource...

1 Answer

Have B&S 7500 Vanguard Genset. No Output. Have checked windings as per info on this site. Applied 12Vdc direct to the brushes and get 160Vac output. There are black/red wires from brushes that go back...


Hi, a word of caution, use a 9volt battery instead of 12v to check the rotating field winding. The 12volts from a car battery or battery charger can burn out windings in a generator. I would say that your avr is pooched. There are 4 leads that go back to the windings in the generator from the AVR. Two of these are connected to the power output and two go to a separate winding in the generator. This is the exciter winding and this supplies power to the avr for the rotating field. The two to the power output are voltage reference only. If your generator has these exciter winding, you should check if you have voltage there with the 9 volts applied to the rotor. If you have voltage on the power output and not on the exciter, then the exciter is shot and your avr might not be. Try this first, if you could, could you take a picture of the windings at the back end of the generator, this will confirm for me what leads you have present.

Feb 15, 2011 | Briggs & Stratton Electrical Supplies

1 Answer

I have a Stamford alternator model UCI247E I'm trying to restrap it from 220/380v to 120/208 can anyone help?


http://www.marathonelectric.com/generators/linkBoard.jsp

Look under Low Voltage (Parallel ) WYE Connection This is for a 12 lead alternator. I believe this is what you have. This will give you 120 / 208v 3 phase. Make sure that your connections are strong physically and well insulated electrically to prevent a nasty accident. This is a good, solid, dependable unit. Make sure that you have your frequency set around 61- 62 hz (depending on load) so that when the unit is loaded, the frequency drops to 60 hz. I have seen many units set to run quietly and save fuel. This being done, the rpm is too low and the output frequency is below 50hz. Anything with a coil (motors, transformers) will burn out due to an improper frequency.

Dec 05, 2010 | Electrical Supplies

1 Answer

I want to reverse rotation on my A.O. Smith 120/230 volt single phase 1.5 HP motor. Catalog number B762


I believe all you have to do is swap your two hot wires,that works for 3-phase but not sure on single phase

Oct 07, 2010 | AO Smith 1 1/2 HP 115/230V 56C Replacement...

1 Answer

My generator is not putting out the proper voltage? it's only putting out approx 75 volts on the 120 volt circit. i adjust the idle to full out and i get approx 112v.


Most low voltage conditions on generators are simply due to a low engine rpm. Most modern generators are 2- pole windings. So your engine rpm should theoretically run @ 3600 rpm. which will produce 120/240 volts @ 60 HZ. In actuality You want to set your rpm's @ Approx. 3720rpm no load. About 62.5 Hz. Without getting to technical this will give you your desired 120/240 volts loaded. Hope this helps.

Aug 09, 2010 | Northstar Electrical Supplies

1 Answer

Trying to wire up a single phase transfomer, 480 step down to 208


TAKE ONE OF YOUR 480VOLT WIRES AND TIE IT WITH (H1) TAKE THE OTHER 480VOLT WIRE AND TIE IT TO (H4) NEXT TAKE TRANSFORMER WIRES (H2) &(H3) AND TIE THEM TOGETHER THAT WILL TAKE CARE OF THE HIGH VOLTAGE SIDE, NEXT WITH YOUR 208V- TAKE ONE OF THEM AND TIE IT TO (X1) TAKE THE LAST ONE AND TIE IT TO (X4). LAST TIE (X2) AND (X3) TOGETHER THEN YOU WILL HAVE IT. -LANCE

Oct 16, 2009 | Acme 1000-Watt Transformer with Dual...

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