Will a Belt-Drive Compressor Run on 13A? What to Check First

You have outgrown a small direct-drive compressor, or your belt-drive machine trips, fills slowly or needs a service.

The essentials: check the supply rating, compare free air delivery (FAD) and drain the tank daily. PartsForMachines lists over 120 compressors from NuAir, SIP, Sealey, Clarke, Draper and Tigren in its Belt Drive Compressor range. They run from 13A machines to three-phase and petrol models.

Will a 3hp Belt-Drive Compressor Run on a 13A Socket?

Many will, but check the input supply figure first. Plenty of 3hp single-phase machines run on 13A, such as the Draper 55315 200-litre belt-drive compressor, which gives 8.44 CFM FAD. Higher-output 3hp models may need 16A, twin-motor tandems 32A, and electric machines of 5.5hp and above are generally 400V or 415V three phase.

Anything rated above 13A needs a suitably rated circuit to start and run reliably, so have an electrician fit one. Some machines also have starting aids: several 3hp units use twin capacitors and a centrifugal switch, and most single-phase tandems start their motors in turn.

Displacement or FAD: Which Figure Should I Compare?

Compare FAD. Free air delivery is the air actually delivered at the outlet, converted back to intake conditions, so it matches what your tools use. Displacement describes the pump and is always the larger figure across our range.

The VN3/150-SB vertical compressor, for example, turns 13 CFM displacement into 8.5 CFM FAD, about two-thirds. So a 4 CFM spray gun has more headroom on 8 CFM FAD than on 8 CFM displacement. Where a spec gives displacement only, expect less usable air. Then add up the air use of the tools you run together and keep it within the FAD.

Is a Belt-Drive Compressor Worth It Over Direct Drive?

Yes, if you want a pump that runs slower and cooler, which can extend its life. A direct-drive pump turns at motor speed, while a belt and pulleys let it run slower: 1,100rpm on the 55315, for example. On some models the belt drive also helps keep noise and vibration down. The trade-off is that belt tension and pulley alignment need periodic checks.

Belt drive is not the same as quiet, though. Many open machines are rated at 96 to 97 dB(A), so hearing protection is advisable nearby. In its enclosed cabinet, the SAC2203BLN low-noise compressor is rated at 68 dB(A) at 1m.

Is Rust Inside a Compressor Tank Dangerous?

Heavy rust can be. Corrosion thins the receiver wall, which in extreme cases can make it burst, so take a badly rusted tank out of use and have it examined by a competent person. Never weld, drill or patch it.

Prevention is simple. Open the drain valve after each day's use, unless the tank has an automatic drain, because water left inside rusts and weakens it from within. Then inspect the tank for rust at least once a year.

What Should I Check Before I Buy?

• The supply: 13A, a higher-rated single-phase circuit (16A to 40A on bigger units), or 400V/415V three phase.
• FAD against the combined air use of the tools you run together.
• Maximum pressure: most run to 10 bar (145psi), some to 11 bar and a few to 8 bar.
• Receiver size and layout: a vertical unit saves floor space.
• A drain valve and an aftercooler to deal with moisture.

Not sure which suits your workshop? Contact the PartsForMachines team by WhatsApp, telephone or email with your supply, tools and space, or browse the Belt Drive Compressor range.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Why does my compressor trip the breaker when it starts?

Suspect the start-up surge: for a split second a motor draws several times its running current. Check that the unloader hisses briefly at cut-out, so the motor restarts unloaded. Plug straight in, since an extension lead can drop the voltage; use a longer air hose.

Which breaker suits a belt-drive compressor?

A type C usually copes better with motor starting: it trips at five to ten times its rating, against three to five times for a type B. Some makers specify time-delay protection, so ask an electrician whether your circuit suits a motor load.

Why does my compressor stop after a long run?

The thermal overload may have cut in: it stops the motor when it gets too hot. Unplug the compressor and let the motor cool before restarting. If it keeps happening, contact our team with the model and how you use it.

Why is my compressor slow to build pressure?

Either air is escaping or the pump is under-delivering. Brush soapy water over joints while it runs to find leaks, re-tension a slack or squealing belt and clean the intake filter. If all that checks out, suspect a broken valve or leaking head gasket.

How tight should the drive belt be?

Set it to your manual's deflection figure, measured at the centre of the span. A slack belt slips and runs hot, while an over-tight one can wear the bearings early. Isolate the power and release the air before adjusting, and check pulley alignment.

What oil should go in a belt-drive compressor pump?

Use your manual's grade, usually ISO 100 (SAE 30) compressor oil. Makers often call for a first change at 40 to 50 hours, then every three months or 500 hours. Synthetic is fine where the manual approves it and usually lasts longer between changes.

Is three phase better if I have a three-phase supply?

For larger machines, usually yes: three phase gives smoother starting and running. Output can be the same. The PX4-3/200B three-phase compressor gives 14 CFM FAD on 400V, as does the single-phase PX4/200B on 18A. A three-phase machine will not suit single-phase sockets.

When does a petrol compressor make sense?

Where there is no mains, or too little electrical capacity. For tyre and impact-wrench work in fields, the B3800/5.5S/10+10 petrol compressor weighs 80kg and loads onto a van or trailer. For a remote or farm workshop, the static SA1565 gives 15.2 CFM FAD.

Can I set up and service a belt-drive compressor myself?

Placing it and routine care, yes; a new higher-rated circuit is an electrician's job. Stationary machines are heavy (the NB38/270 tandem weighs 215kg), so plan for help. Check the pump oil level before each use and keep the belt guard fitted.