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Just a quick line to thank all of the people on this forum, I have asked many a stupid question ( before you say anythingt andy c I know there are no stupid questions ) and have been amazed at your replies and constant help, I have been out of the installation industry for approx 20yrs and have...

Afternoon all, what two test should I carry out on a replacement motor ???. I have checked DOR and info on the plate all match the existing motor. 1 insulation resistance across L and N ( what range 500v dc/ 250v dc ) ????? 2 continuity of CPC to motor housing ???. Can some one please...

What happens to the power output in a resistive circuit if the voltage doubles ??, would it be the same for an inductive circuit. Thanks for looking. NWDS

Afternoon all thanks for your time, Iam stuck on this I cannt get me head around it, when Iam given resistance and power I struggle to work out voltage or current. Example 1, if a 0.5 watt lamp consumes a current of 200mA. What voltage of battery should be fitted ????. Example 2, What current...

Test on a 300m lenght of single core MIC produced the following results: conductor resistance 2.4 ohms, insulation resistance 40 Mohm. What will the anticipated conductor and insulation resistance values of a 120m lenght of cable. I worked it out as follows, 300/2.4 = 125 ( 1/125 = 0.008 ) so...

sorry all, Three pvc insulated cables are connected in parallel, and their resistances are 0.012, 0.015 and 0.008,respectivley,with a total current of 500A flowing on a 240V supply, A, calculate the current in each cable ( V/R = I ) B, calculate the combined voltage drop over the three cables...

Q1, A cable carries a current of 65 A with a volt drop of 13v. What must the resistance of a cable wich, when connected in parallel with the first cable, will reduce the volt drop to 5V. Q2, To vary the speed of a D.C. series motor it is usual to connect a diverter resistor in parallel with the...

can some one help with this ????? what is the VD across R4 & R5. R1 6 ohms R2 7 ohms paralell with R1 R 3 8 ohms series R 4 9 ohms R5 10 ohms in paralell with R4 supply voltage is 50v the answer is 14.82v thanks in advance NWDS

When using ohms law I have noticed in some equations that I sq and V sq is used can some one explain why ??????. NWDS

can some one check this for me please ( andy c ),0.707* peak gives you RMS. 0.707*325.18 ( peak )= 230 rounded up 230 (RMS )/0.707 = 325.18 peak ???? 230 ( RMS )*1.414 = 325.22 peak ??? 325.22*325.22 = 650.44 peak to peak. Thanks in advance for checking fellas. NWDS

Afternoon everyone, can some one check this ??? please A transformer is rated @10kW but is only delivering 9.8kW, copper losses are 0.33kW & iron losses are 0.2kW, calculate the efficiency of the transformer. Answer given is 90.4% output/input ( + losses ) = 90.4% 9.8/10.83*100 = 90.4%...

morning all, just a quick question This is how its wrote, A single phase load @ 400v ( 3ph ) AC is rated @ 6.4kW and has a power factor of 0.8, calculate the design current. Answer is 11.5 amp So 1000/(1.732*400*0.8)= 11.5 amp 1.732*400 = 692.8 692.8*0.8 = 554.24 1000/554.24 = 1.804...

Evening all can I have some help please, what is the total power in the circuit shown here if, R1= 6 ohms ( 1/6 = 0.1666 ) R2= 7 ohms ( 1/7 = 0.1428 both in parallel ) R3= 8 ohms ( series ) R4= 9 ohms (1/9 = 0.1111 ) R5= 10 ohms (1/10 = 0.1 both in parallel ) the supply voltage is 50v, I...

Evening all can some one please help. I have stumbled across this question and cannt work it out 18 If 12.50/10 electrons pass through a wire every second, what is the current in amps ???? I have the correct answer but cannt figure out how to get there thanks in advance fellas. NWDS

Afternoon/evening all, I have just installed a new ring in a kitchen,6 d/skts, before the plasterer has been in I have checked continuity of ph/ph 0.25 ohms N/N 0.36 ohm why would I get such a difference in my readings ?? , I have ckecked all the connections ( fronts off and connectors used )...

I have a job to do ( new kitchen circ ), my question is that it has 2 stop taps within 350mm of each other ( lead ), I know I have to bond within 600mm and was going to bond after the second stop tap am I right ???????????. NWDS

I have bought a motor starter TEW 11A 12A, 240v 50Hz AC3 5.5kW 7.5 HP my question is were to connect my +/-, am I right in thinking my - connects to A2 and my + to A1 ?????????????. also I have a start and stop button that have 2 leads coming out of them do these connect onto the overload...

Evening fellas, am I right in thinking that when you have worked out the volt drop ( mV*A*M/1000 ) if this is greater than the values given in the OSG ( pg 124 ) then you would have to recalculate untill you could meet the values ??????????????. NWDS

Evening fellas, sorry to bother you all with this one but Iam bending some pvc and cannt get it right ( 90 & double set ), any help would be great. NWDS

Evening fellas, Iam trying to find out what I need to build one from scratch to use on a test bench so I can familiarise my self with how they work. NWDS