The compressor is not shorted to ground and has no open windings. When using current measurement to determine motor load, it is important that correction be made for the operating power factor. if 14 amp motor pulls 56 amps on startup depending if circuit breaker is fast reacting or slow reacting in time. Motorhome 5th Wheel and Camp Trailer Roof Top Air Conditioners: Watts Required for start up: Average wattage once running: 7000 btu RV air conditioner Both seem good - 11 to 12 amps and 15 degrees F differential. Approximately 15 amps. Compressor discharge valve leaking. I tried out the compressor on a 30 amp breaker and it ran fine. Using the amperage draw of the compressor will help any technician determine if the compressor is truly defective. Solution: Current = [0.5 * 746] / [220 * 0.88 * 0.9 * 2] = 1.07 Amps. However, because they are permanently mounted, central air units are hard-wired into your electrical box. This generator sizing sheet will help you to determine your running and starting watts so you can choose the correct generator for your needs. Incorrect starting relay. Troubleshoot compressor issues A compressor showing locked rotor amps may show some of the following symptoms. I live off-grid and last year ran the AC no problem with my 10KW military surplus diesel generator. P (W) = PF × I (A) × V (V). If the replacements do not bring your HVAC compressor back to life, you have two options. I have a larger 1.75 hp motor on a table saw and it only pulls 3 amps with no load, so seeing 12 on the smaller compressor motor with no load surprised me. If the service technician now actually measures the compressor amps with an ammeter at the compressor and finds the amps to be very close to 29.4 amps, he has a pretty good idea that the compressor is up to specifications. I tried starting my AC and the blower motor came on and then when the compressor goes to start it just stops. Unfortunately, as the compressor ages, it has trouble starting (called hard starting) and pulls even more electricity, causing the breaker to trip as a result. For AC devices you have to include the power factor. 08-23-2019, 09:36 AM #2. If the compressor continues to pull high amperage it may … Newer AC with Puron technology that I believe is 3.5 ton unit. Belt Sander Air Compressor – 1/4 HP Air Compressor – 1 HP Computer w/17 in. SO A 5 TON AC WOULD BE AROUND . If the cost of a replacement is less than half of the cost of a new unit, this is most likely your best option. Diagnosing a defective compressor can be tricky at times. The auxiliary coil, also called starting coil, is used to create an initial rotating magnetic field. As a thumb rule, consider each ton will take 1300 watts. IN ONE HOUR 5 TON AC ASSUMED POWER CONSUMED 6 UNIT /HOUR. You may have a technician replace your compressor, or you may decide to replace the entire air conditioning system altogether. Check the specifications with the compressor manufacturer. ... most motors pull 400% amps on startup easily confirmed using a clamp on amp meter. The current builds up in milli-seconds when the compressor contactor closes at start up and decays to the running current over 100-200 milli-seconds (the time it takes for the motor to start Central A/C Fan Only – Compressor Off – 750 Watts. In most cases, people are interested in how many amps does a 5,000 BTU air conditioner use. A "hard starting" "tight" air conditioner compressor will probably draw excessive current (Amps) during startup, so that measurement may be used as part of the diagnosis of this problem. Air Conditioner Compressor Hard Start FAQs Q&A on diagnosing, fixing an AC compressor that has trouble starting - These questions & answers about hard-starting air conditioner or heat pump compressor motors help diagnose why the motor may hesitage, be slow starting, or may continue to burn out the starting capacitor. The power P in watts (W) is equal to the current I in amps (A), times the voltage V in volts (V):. I did very basic tests in AC mode, checking compressor amps after running them for 30 minutes and measuring the return and supply air temp differentials. Furthermore, how much power does a 5 ton air conditioner use? Re-Starting a Tight or Seized Air Conditioner Compressor Amps = Watts ÷ Volts. Central air conditioning also runs on 230 volts. knowing and understanding how to use amp probe is very important in air conditioning industry. Generally a higher wattage generator lets you power more items at once. Largest Window Units – 1440 Watts. The current draw of air conditioners is rated in amperes or amps -- the basic unit of electricity that is equal to a constant current draw. The volts multiplied by amps = watts only works for DC current. Air conditioners are rated on their cooling properties, as measured in British thermal units, or BTUs. 5) Compressor has trouble starting The heart of your AC system is the compressor. These are approximate values only. Single and three-phase are the norms. 17 C. Capacitor Start and Run (CSR) This motor arrangement uses a start capacitor and a run capacitor in parallel with each other and in series with the motor start winding. Current Rated load current in amps is at nameplate horsepower (HP) with nameplate voltage and frequency. In example a 40 amp 240 volt or 208 volt will draw approximately 9600 Watts at 240 and approximately 8320 Watts at 208. From page 5 for a 12 SEER Bryant heat pump - a 5 ton unit draws 27.6 amps for the compressor and 1.4A for the fan. The nameplate shows 17.9 RLA and 90 LRA. A hard start kit is an energy-storing capacitor that helps your AC start when it’s struggling to turn on.. Like their name suggests, hard start kits help solve a problem called hard starting, which is when an AC struggles to turn on and then shuts off abruptly after a short while.. The three-phase ac amps involve HP * 746 in the numerator and 1.73 times PF * Efficiency times voltages in the denominator. Remember, the compressor must be operating at the proper voltage for the table to be meaningful. Means 2 ton = 2600 watts Considering the AC as single phase Just apply it in formula P=V X I X Cos phi I = 2600 / (240 X 0.8) = 13.54 Amps. 1.1 KW/TON X 5 TON = 5.5 KW ( 1 kw consumed electricity in per hour = 1 unit . So the VA for this unit at 240V is 6960. This represents the number of ac power lines supplying the motor. The size of the generator you need depends on your power requirements. The larger the BTU number, the more amps the air conditioner will draw. Compressor pull high amps. The compressor may make a humming sound, that may increase in sound level over time. Electric Drill – 3/8 in., 4 Amps Electric Drill – 1/2 in., 5.4 Amps Circular Saw – 7 1/4 in. I think the motor, pulleys and the compressor is just too much inertia for a single phase motor to soft start. Thus, the current in amps is equal to horsepower times 746 divided by the voltage times the efficiency η times the power factor. One way to improve on the single coil design is by using an auxiliary coil in series with a motor starting capacitor. AC single phase amps to watts calculation. The formula is identical to the previous case with the difference of factor 1.73 instead of 2 in the denominator. Of course, you also have 6,000, 8,000, 12,000, 15,000, and 18,000 BTU devices that use more amps than 5,000 BTU units. Start capacitor AC induction motors. Compressor Motor and Component Information. Wattage / Engine / Run Time / Starting / Mobility. P (W) = I (A) × V (V). The power P in watts (W) is equal to the power factor PF times the phase current I in amps (A), times the RMS voltage V in volts (V):. Appendix LRA - Locked Rotor Amps: The current you can expect under starting conditions when you apply full voltage. I changed generators to a 12.5KW diesel model with an Isuzu diesel engine. 4 ton 13 SEER heat pump condensing unit - max 45 amps and min 26.4 amps. For safety use breaker rating of 20 Amps In the link Marc referenced above Jimmy quotes using 3 times the running wattage as a rule of thumb for a starting wattage. It spins easily by hand and is a pretty simple design using reed valves and a simple felt-like intake filter. My question has to do with heat mode. As a rule of thumb it takes about 12 DC amps to run 1 AC amp after taking voltage and efficiency factors into consideration. Suction pressure high - High superheat at evaporator outlet. 1 Ton yields approximately 10 amps of draw. The compressor appears to work normally other than the high current draw. After the steps above the final formula for converting horsepower to amps is: Amps = HP × 746 V × η × PF. It pulls tons of electricity when it starts up. Soft starting the air compressor's capacitor start capacitor run motors while the compressor drive belt is tensioned with my varrac I was only able to reduce starting amps from 45 down to 35. I feel that is … This is nowhere near 18 KW but real close to the 1 HP per ton which MD uses. Window AC - 12,000 BTU: 3250* Central AC - 10,000 BTU: 1500* Central AC - 24,000 BTU: 3800* Heat Pump: 4700 * Allow 2 times the listed running watts for starting these devices. Three phase AC. DC amps to watts calculation. How many amps does a 2.5 ton AC draw? Unbalanced system, load in excess of the design conditions. The electrical current (measured in Amperes or ‘amps‘ for short) needed to run an air conditioner is directly proportional to how much the AC unit will affect your electricity bill. So, if you have a 10 Amp compressor , you need to depend on at least a 120 Amp draw from the battery, or 1440 watts (120A x 12VDC). Although amp draw can vary a lot according to a lot of factors (how dirty the condenser coils are, load, how hot it is outside, etc), I would expect a 3 ton compressor to pull around 15 amps on start up and then taper off to around 11-12 amps when it's running Appliance Watts/Amps Calculator Electricity is measured in units of energy called watts, named after James Watt, the inventor of the steam engine. Often times a system problem may seem to be the result of a defective compressor when in fact it is due to some other cause. Watts is generally defined as the amount of power (or energy) an appliance uses (consumes) when operated at its maximum capacity for 1 hour . The windings ohm at: C to S - 1.4 C to R - .9 S to R - 2.1 One of the other technicians condemned the compressor, but other than the high amp draw the compressor would not indicate any problems.