Hi, i have an old allen bradley starter with line voltage control circuit for the coil, 230 volt corner ground system. There is a control circuit running through contact terminals on the bottom of the overloads. I am replacing it with a new starter, sq.d and it doesn't have the nc. contacts available. I don't want to use a standard relay because of the 230 volt coil voltage. Does anyone have a solution to interlock a control circuit to modern overloads?
If is a " starter" it wil have an overload relay with a NC contact. The newer IEC style starters are actually two components . The contactor and the overload realy assembly. These overload asembliess come in various ranges of current depending on the motor. They usually have both a NO and a NC contact. You didn't furnish the model number of the new starter. You are correct to use a starter to match the overloads to the motor current, not a contactor.
First off check the battery visually, do a voltage and a load test and check all connections at the battery and the starter to ensure that the system is operational.
If the starter clicks a lot the battery is likely low on charge or simply no good. Charge it and check it.
If the battery is good and has proper voltage and the starter relay clicks but the starter does nothing or turns slowly or stalls do a starter circuit voltage drop test.
VOLTAGE DROP Testing checks the integrity of all wiring, switches, circuit breakers, fuses and connectors between the source and destination while under load by measuring the difference in voltage/potential (the actual voltage dropped between the source and destination). In this starter test because we are assuming that the starter relay clicks which shows that it is working it will simply be a test of the circuitry between the battery, starter and ground. If the relay was/is the problem you would have battery voltage at the battery cable stud on the solenoid but you would not get any current through the solenoid to the starter terminal.
The benefits of this manner of testing are great. The readings are not very sensitive to battery whatever actual battery voltage is and the readings show the actual voltage dropped not that voltage is present. It is quicker and easier and more foolproof and more accurate than other means of circuit testing such as resistance testing with an ohmmeter and it tests the circuit as it is actually used and it will show up otherwise hard or very hard to find poor connections (high resistance) etc.
This system of voltage drop testing can be used on starter circuits, lighting circuits, ignition circuits, and etc. Always start from most positive point which is most likely always going to be the battery positive post and go to most negative point which is the point at the end of or through or after the electric current will have gone through most or all of the circuit to be tested I.e. the destination point or the destination component, for example the starter relay terminal at the starter or the starter connection after the solenoid of you want to check resistance all the way through the system including the solenoid contacts.
First do a voltage reading on the battery and note what it is.
Using a voltmeter attach the red meter lead to the most positive part of the circuit, which would be the positive post of the battery and attach the black meter lead to the final destination or component in the circuit (if testing a starter circuit this would be the terminal on the starter, not the solenoid). THEN try to activate the starter and observe the meter reading. The meter will read the voltage dropped or the difference in potential between the source and the destination. An ideal circuit voltage drop reading would be 1 volt or less. If there is an open in the circuit (i.e. NO electricity is reaching the terminal) the voltmeter should read source voltage volts which means all the voltage was dropped. A normal good starter circuit should not show more than a one volt drop. If more than 1 volt is dropped there is a problem somewhere in the circuitry before the starter terminal. In this case leaving the red voltmeter lead on the battery positive post, move the negative voltmeter lead to the solenoid stud where the battery cable attaches and activate the starter circuit again. If the voltage reading is now 1 volt or less clean, repair, tighten the starter solenoid to starter terminal stud connections and test again and if no change clean/repair the internal solenoid contacts or replace the solenoid with a new/good one. If there is still a voltage drop greater than 1 volt move the negative voltmeter lead from the solenoid terminal stud to the actual battery cable terminal end at the solenoid terminal stud and again activate the starter circuit. If there is a 1 volt or less reading the battery cable terminal end and/or solenoid terminal stud and/or the connection between the two is faulty, loose, corroded or etc. Clean and tighten and retest. If there is still more than a 1 volt reading on the voltmeter the problem is a loose or corroded or otherwise bad connection between the battery cable terminal end and the battery positive post or the battery cable itself is bad. Clean and tighten the battery cable terminal and battery positive post and test again. If there is still more than a one volt reading on the voltmeter the battery cable is bad and will need to be replaced.
If there is less than a 1 volt reading when the test is done at the starter terminal the circuit up to that point is good so the next step will be to do a negative or ground circuit voltage drop test by connecting the negative or black voltmeter lead to the most negative point which is normally the negative battery post (or the closest thing thereto if, like some Sportsters, the battery post is hard or impossible to get to) and then connect the positive or red voltmeter lead to the starter mounting studs. Then activate the starter circuit again and if the voltage reading is greater than 1 volt clean the battery negative cable ends and battery post and negative cable to motorcycle frame or other grounding point, tighten same and similarly the starter mounting points and studs because there is a problem with the starter ground (could be looseness, corrosion, powder coat/paint problems etc). If the voltage reading is 1 volt or less than 1 volt in this test the ground circuit is okay and it will be necessary to perform a starter current draw test on the vehicle (and/or a starter current free draw test on the bench). If the results are within the specifications for the starter in these tests remove the spark plugs, raise the rear wheel so it can spin unimpeded, put the transmission in 5th gear and rotate the rear wheel to check for engine, transmission, primary and/or crankshaft resistance/bind. If the results are not within the amperage specifications for the particular starter replace or repair the starter motor to bring within the system amperage specifications.
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