Spektrum
Firma 3900Kv 4-Pole Brushless Motor
Firma 3900Kv 4-Pole Brushless Motor
SKU:SPMXSM3300
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The Spektrum Firma 3900 Kv 4‑Pole Brushless Motor is a high‑RPM sensorless upgrade for 1/10‑scale 4WD vehicles like the ARRMA GROM BLX. Featuring a low‑cog 4‑pole rotor, CNC‑machined aluminium housing, pre‑installed bullet connectors and a durable 5 mm steel shaft, it delivers smooth, efficient performance at 3S voltage levels.
Features
- Sensorless brushless inrunner with high‑tolerance 4‑pole rotor design
- CNC‑machined aluminium can, insulated high‑purity copper windings
- 5 mm hardened alloy steel shaft (supports SafeD‑5 pinion)
- Pre‑installed 4 mm gold‑plated bullet connectors
- Ideal for 1/10 scale models running up to 3S LiPo
What’s in the box
- Spektrum Firma 3900 Kv brushless motor with connectors
- Instruction manual
Needed to complete
- Spektrum Firma Smart ESC (e.g. 130) or compatible standard ESC rated ≥ 45 A
- 2S–3S LiPo battery (7.4–12.6 V)
- Full‑range transmitter and receiver for your radio system
Specifications
- KV rating: 3 900 Kv
- Application: 1/10‑scale surface vehicles
- Input voltage: 2‑3S LiPo (up to 12.6 V)
- Maximum continuous current: 45 A
- Approximate output power: 1 420 W @ 3S
- Efficiency: 80 %
- Outer diameter: 36 mm (1.4 in)
- Length: 60 mm (2.35 in)
- Shaft diameter: 5 mm (0.2 in)
- Weight: approx. 253 g (8.9 oz)
- Connector type: 4 mm gold‑plated bullet
- Technology: Sensorless 4‑pole brushless motor
Frequently Asked Questions
When will my order be shipped?
Orders placed before our daily cut-off time are usually shipped the same or next working day.
You’ll receive tracking details as soon as the courier collects your parcel.
How long will delivery take?
South African deliveries typically arrive within 1–3 working days, depending on your location.
International delivery times vary based on the destination.
Can I collect my order?
Yes. Collection is available from our Somerset West warehouse during business hours.
Where are you based?
We’re based in Somerset West, Cape Town, South Africa, and ship throughout South Africa and worldwide.
Do you ship worldwide?
Yes — we offer worldwide shipping.
What payment methods do you accept?
We accept secure online payments, including card payments, instant EFT, PayPal, and other major South African payment methods.
In-store card payments are available via Yoco.
Will I receive a tracking number?
Yes. Tracking information is emailed automatically once your order has been dispatched.
Do the products include a warranty?
Most items include a manufacturer-backed warranty.
Warranty terms vary by brand and product type.
Is my order safely packaged?
All items are securely packaged to minimise the risk of damage during transit.
Can I change or cancel my order?
If your order hasn’t been shipped yet, we can usually assist with changes or cancellations.
Please contact us as soon as possible.
Do you offer dealer or wholesale pricing?
Yes — eligible retailers can apply for a dealer account.
