Screw Compressor ASC-7-10-200A, 5.5 kW (direct drive, permanent magnet motor, with frequency converter)

1. Purpose and Operating Principle

The unit is equipped with a frequency converter (VFD): the speed of the screw pair is smoothly adjusted to match current air demand, so the compressor does not run in a full-power “start/stop” cycle but adapts to the load instead — this reduces peak starting currents and smooths out network pressure. Compressed air passes through the air-oil separator into the built-in 200 l receiver, from where it is delivered to the pneumatic network via the outlet fitting.

The lower power rating (5.5 kW), compared to the range’s larger ASC-10-10-200A model, makes this a good fit for consumers with moderate and variable air consumption — where partial-load energy savings and minimal noise/vibration compared to a belt-driven scheme matter.

2. Technical Specifications

⚠️ Unconfirmed parameters (require verification with the manager/datasheet before publishing):

• Compressor type (oil-injected/oil-free) — oil-injected is assumed by default, but this is an assumption, not a confirmed fact.
• Supply voltage — typically 380 V / 50 Hz for stations of this class; requires confirmation.
• Screw element manufacturer
• Outlet fitting (connection size, inches)
• Noise level, dB(A)
• Weight and dimensions (length × width × height)
• IP rating and insulation class of the electric motor

3. Design Features

Model code breakdown:

Design solutions:

• The screw element rotor is mounted directly on the motor shaft — eliminating the belt assembly entirely (no belt slippage, no scheduled belt tensioning or replacement).
• Permanent magnet motor — higher efficiency at partial loads compared to an asynchronous motor of the same power rating.
• Built-in frequency converter — soft start and output regulation matched to actual air demand, instead of a “full load/idle” cycle.
• Built-in 200 l receiver — dampens pressure pulsations and reduces compressor cycling frequency.
• Open layout (no soundproof enclosure) — easier access to service components, but a higher noise level than cabin-enclosed units (see “Application” section).

4. Installation Recommendations

• Install on a flat, level base with clearance around the perimeter (at least 0.6–0.8 m) for free air circulation and servicing — this is an open-type unit, cooled directly from the room.
• Provide a dedicated power line with protection sized for the starting current of the PM motor with the frequency converter (starting currents are lower than a direct-on-line start of an equivalent asynchronous motor, but the line should still be sized from datasheet values, including the supply voltage, which needs to be confirmed with the supplier).
• Connect to the pneumatic network via the outlet fitting thread ⚠️ (type and size not confirmed for this model):
  • If the fitting is BSPP (G, parallel) — sealed with a flat gasket; no PTFE tape required.
  • If BSPT (R, tapered) — a self-sealing connection; PTFE tape or equivalent sealant is required.
• The room must have supply-and-exhaust ventilation: an open-layout compressor releases heat directly into the room.
• Fit the 200 l receiver with an automatic or manual condensate drain and check the safety valve periodically.
• The frequency converter is sensitive to power quality — where mains voltage is unstable, a stabilizer or UPS for the control board is recommended.
• If the network will supply pneumatic tools that require lubrication (impact wrenches, impact grinders), install a separate line lubricator downstream of the receiver — the compressor’s separator is not designed to provide metered tool lubrication.

5. Alternatives and Comparison

⚠️ No verified cross-reference part numbers exist for the ASC-7-10-200A in open sources — the vague claim “alternatives are available” is deliberately avoided. Below are stations of the same class (5.5 kW, direct drive/PM, similar delivery) for reference; verify parameters against each model’s datasheet before substituting.

Comparison with neighbouring line models: the ASC-7-10-200A trails the larger ASC-10-10-200A in both delivery and power (5.5 kW / 800 l/min vs. 7.5 kW / 950 l/min), while receiver volume is identical between the two — 200 l — which gives the smaller model relatively more buffer capacity for its own delivery rate.

6. Common Mistakes

• Installing the unit in a cramped, unventilated room — overheating of the PM motor and converter electronics, triggering thermal protection.
• Ignoring the receiver’s condensate drain — moisture buildup, corrosion inside the receiver, and water entering the pneumatic network.
• Feeding compressed air directly to a pneumatic tool requiring lubrication without a separate lubricator — accelerated tool wear.
• Applying PTFE tape to the cylindrical (BSPP) thread of the outlet fitting “just in case” — this thread type must be sealed with a flat gasket; extra tape can disrupt the fit and cause misalignment.
• Connecting to an unstabilized power supply with significant voltage sags — incorrect frequency converter operation, up to emergency shutdowns.
• Skipping scheduled maintenance of the separator and filters on a unit with frequently changing load (the converter causes more frequent regulation cycles) — accelerated element fouling.

7. Application

This unit is designed for sites with a moderate, variable compressed air consumption profile: small workshops, auto service centers, woodworking and metalworking areas, food and packaging lines — anywhere air demand fluctuates during a shift rather than staying constantly at maximum. The frequency converter and PM motor make this model more energy-efficient specifically under uneven load, rather than round-the-clock operation at 100% capacity.

The open (non-cabin) layout calls for installation in a separate technical room or compressor room rather than in a shop floor next to workstations, due to its higher noise level compared to soundproofed units.

8. Expert Opinion

“Direct drive and a permanent magnet motor are what genuinely cut maintenance and electricity costs on compressors with a variable load. No belt means no scheduled belt replacement and no slippage losses, and the converter lets the unit ‘breathe’ according to actual air demand instead of constantly running at full power for nothing. For sites where 800 l/min is enough, the ASC-7-10-200A with its 200 l receiver gives a good buffer for smoothing demand spikes,” notes Vitali Boluchevski, Lead Engineer, Acvatron SRL, 18 years of experience.

9. FAQ

Does the receiver’s condensate need to be drained manually every day? If an automatic condensate drain is installed — no, but periodic manual checks of the valve are recommended to confirm it’s working correctly.

Can this unit be connected to a pneumatic tool that requires lubrication, without a lubricator? No — the compressor’s built-in separator does not replace metered lubrication; such a tool needs a separate line lubricator installed downstream of the receiver.

How does this model differ from the larger ASC-10-10-200A? In motor power (5.5 kW vs. 7.5 kW) and free air delivery (800 l/min vs. 950 l/min), at the same working pressure (10 bar) and the same receiver volume (200 l).

Is this model suitable for continuous operation at maximum load? A unit with a frequency converter performs best under a variable consumption profile; for constant operation at 100% load, the inverter’s economic benefit is smaller — this scenario is worth discussing with the sales manager when selecting a unit.